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  • (Sept, 2007)

    SCS Installation, Operation & Maintenance Manual

    Air Technology Systems, Inc.

  • (Sept, 2007)

    SCS Installation, Operation & Maintenance Manual

    Air Technology Systems, Inc.



    A A = 0F Fan Cycling/Fan Speed/-30F

    Flooded Head Pressure Control

    SA = -20F Variable Speed Control

    EC = Intelligent Control

    Nominal Capacity in

    1,000s of BTU/H

    SCS Series


    This document contains information protected by copyright. All rights are reserved. The owner of the equipment forwhich this manual is written may photocopy the contents of this manual for internal use only. No part of this docu-ment may be photocopied, reproduced, or translated into another language for use by anyone other than the ownerof the equipment for which this manual is written without the prior written consent of Stulz Air Technology Systems,Inc. (SATS).

    This document contains confidential and proprietary information of Stulz Air Technology Systems, Inc. Distributing orphotocopying this document for external distribution is in direct violation of U.S. copyright laws and is strictlyprohibited without the express written consent of SATS.

    Unpublished rights reserved under the copyright laws of the United States and of other countries.Other brands and tradenames are trademarks of their respective owners.

    Copyright 2007 by Stulz Air Technology Systems, Inc.Printed in the United States of America.All rights reserved.

    Stulz Air Technology Systems, Inc.1572 Tilco DriveFrederick, MD 21704USA


    S = Single Circuit

    D = Dual Circuit

  • (Sept, 2007)

    SCS Installation, Operation & Maintenance Manual

    Air Technology Systems, Inc.

    1.0 Introduction ....................................... 1-11.1 General ...................................................... 1-1

    1.2 Product Description ................................... 1-1

    1.2.1 Capabilities and Features .......................... 1-1

    1.2.2 Application Ranges .................................... 1-1

    1.2.3 Safety Features ......................................... 1-2

    1.2.4 General Design .......................................... 1-2

    1.3 Product Warranty ...................................... 1-3

    1.4 Safety ........................................................ 1-4

    1.4.1 General ...................................................... 1-4

    1.4.2 Safety Summary ........................................ 1-4

    2.0 Installation ......................................... 2-12.1 Receiving the Equipment. .......................... 2-1

    2.2 Site Preparation ......................................... 2-1

    2.3 Rigging ...................................................... 2-1

    2.4 Mounting/Placement .................................. 2-1

    2.5 Piping Connections .................................... 2-2

    2.5.1 Refrigerant Line Sizing ............................... 2-3 Discharge Line ........................................... 2-3 Liquid Line ................................................. 2-4 Weight of refrigerant ................................... 2-4

    2.6 Utility Connections .................................... 2-5

    2.6.1 Main Power/Control Wiring ........................ 2-5

    2.7 System Settings and Adjustments ............. 2-7

    2.7.1 R-22 Refrigerant Charging Procedures ....... 2-7

    2.7.2 R-407C Refrigerant Charging Procedures ... 2-8

    2.7.3 Head Pressure Controls ........................... 2-10 Condenser Fan Cycling............................ 2-10 Variable Condenser Fan Speed ................ 2-10 Flooded Head Pressure Control ................2-11

    2.8 Refrigerant Characteristics ....................... 2-12

    2.8.1 Pressure/Temperature Settings ................ 2-12

    2.8.2 Saturated Refrigerant Pressure Tables ..... 2-12

    2.8.3 Standard Refrigerant Charge .................... 2-13

    2.8.4 Refrigerant Charge Correction Factors ..... 2-13


    3.0 Start-Up/Commissioning .................. 3-13.1 Operation ................................................... 3-1

    3.2 Step by Step Start-Up Instructions ............. 3-1

    3.3 Operational Description.............................. 3-1

    4.0 Maintenance/Repairs ....................... 4-14.1 Periodic General Maintenance ................... 4-1

    4.1.1 General ...................................................... 4-1

    4.2 Troubleshooting ......................................... 4-2

    4.3 Field Service .............................................. 4-3

    4.3.1 Leak Detection .......................................... 4-3

    4.3.2 Leak Repair ............................................... 4-3

    4.3.3 Refrigerant Piping ...................................... 4-3

    4.3.4 Electrical System ...................................... 4-3

    5.0 Product Support Group ................... 5-15.1 Technical Support ...................................... 5-1

    5.2 Obtaining Warranty Parts .......................... 5-1

    5.3 Obtaining Spare/Replacement Parts .......... 5-1

    List of Figures

    Figure 1- Typical Layout .......................................... 1-2

    Figure 2- Ground Mounting...................................... 2-2

    Figure 3- Side Clearance ........................................ 2-2

    Figure 4- Walled Areas or Pits ................................ 2-3

    Figure 5- Piping Installation ..................................... 2-4

    Figure 6- Dual Riser Piping ..................................... 2-4

    Figure 7- Field Wiring .............................................. 2-5

    Figure 8- Sample Nameplate ................................... 2-6

    Figure 9- Flooded Head Pressure Control Diagram ... 2-11

    Appendix A - Forms

    Checklist for Completed Installation .........................A-1

    Periodic General MaintenanceChecks and Service Checklist ..................................A-2

    Appendix B - Glossary

    Definition of Terms and Acronyms ............................B-1


  • (Sept, 2007)

    SCS Installation, Operation & Maintenance Manual

    Air Technology Systems, Inc.



    1.1 General

    The Remote Air Cooled Condenser covered by thismanual is designed and manufactured by Stulz AirTechnology Systems, Inc. (SATS). Recognized as aworld leader, SATS provides precision cooling systemswith the highest quality craftsmanship using the finestmaterials available in the industry. The unit will provideyears of trouble free service if installed and maintainedin accordance with this manual. Damage to the unitfrom improper installation, operation or maintenance isnot covered by the warranty.

    This manual contains information for installation,operation, maintenance, troubleshooting and repair.STUDY the instructions contained in this manual.They must be followed to avoid difficulties. Spare partsare available from SATS to insure continuous opera-tion. Using substitute parts or bypassing electrical orrefrigeration components in order to continue opera-tion is not recommended and will VOID THE WAR-RANTY. Due to technological advancements, compo-nents are subject to change without notice.

    SATS Air Cooled Condensers are designed to rejectheat from refrigerant based cooling equipment. Anyuse beyond this is deemed to be not intended. SATSis not liable for any damage resulting from improperuse. The unit is designed to be installed outdoorsunless otherwise noted on the equipment nameplate.

    1.2 Product DescriptionSATS Remote Air Cooled Condensers are designed tobe the most efficient and reliable condensers in theindustry. The unit is an air-cooled, heat rejectioncondenser with a vertical air discharge pattern.

    The unit is self contained in a light weight, corrosionresistant aluminum cabinet designed for mounting toa horizontal surface. The cabinet houses the con-denser coil(s) and fan assembly(s). The electricalcontrols are in an integrally mounted, weather proofenclosure which is isolated from the rest of theequipment. There are several cabinet sizes based onthe capacity of the unit. Refer to the installationdrawing supplied with your unit for the layout anddimensions of your cabinet.

    The total heat rejection in BTU/Hr will depend on theunit size which can range from 12,000 to 683,000BTU/Hr. Refer to the unit nameplate to identify themodel number of your unit. The system will consist ofa single circuit or dual circuit coil. The coil is aclosed-loop refrigerant condensing heat exchanger in

    which refrigerant is continuously circulated by thepressure differential created by a compressor. Thecompressor increases refrigerant pressure to a levelsufficiently high for it to be cooled and condensed intoliquid by the effect of ambient air being drawn over thecondenser coil. SATS condensers are designed tooperate with either R22 or R407C refrigerant.

    Outdoor air cooled condensers use fan cycling for lowambient head pressure control down to 0F. Variablefan speed control is used for operation in low ambienttemperatures down to -20F. Flooded head pressurecontrol is used with fan cycling for low ambienttemperatures down to -30F.


    SATS condensers are strictly for non-residen-tial applications.

    Operation of the condenser is controlled by a 24 VACinput signal from a system controller provided with theindoor evaporator section or, it can be configured forindependant, stand-alone operation.

    1.2.1 Capabilities and FeaturesAll Aluminum Cabinet ConstructionAluminum Fin Copper Tube Coil ConstructionMounting LegsDirect driven axial fan(s) equipped withexternal rotor motorsUnit Mounted, Weather Resistant Control Enclosurewith Lockable Service Disconnect Switch

    1.2.2 Application Ranges

    SATS remote air cooled condensers are designed foroperation within the following ranges:

    Outdoor Temperature Range:

    Fixed Fan Cycling Control ...................... 0F or higher

    Variable Fan Speed Control ................... -20F or higher

    Flooded Head Pressure Control ........... -30F or higher

    Operating Voltage:VAC Input per unit nameplate +/- 10%.

    Max. Piping Length; Indoor Evaporator to Condenser:150 ft equivalent length.

    Max. Level Drop; Indoor Evaporator to Condenser:20 ft (when condenser is below the evaporator).

    Storage Conditions: ............................... -30F to 105F.

    NOTEDamage or malfunction to the unit due tostorage or operation outside of these rangeswill VOID THE WARRANTY.


  • (Sept, 2007)

    SCS Installation, Operation & Maintenance Manual

    Air Technology Systems, Inc.


    1.2.3 Safety Features

    The remote air-cooled condenser is provided with afactory mounted, service disconnect switch as stan-dard. The service disconnect switch electricallyisolates the unit during routine maintenance. Thehandle of the switch may be locked in the Offposition to prevent unauthorized operation. Fingerguard grilles are provided on each fan to protect theoperator from injury and to keep large tools or otherobjects from falling into the fan.

    1.2.4 General Design

    The remote condenser is housed in an aluminumframe type cabinet and is rated for outdoor use. Figure1 depicts a typical layout of a remote air cooledcondenser and identifies the major components. Condenser Coil

    Each condenser coil is a copper tube, aluminumfinned coil. The capacity of the condenser indicatedby the unit model number, is based on the ratedcapacity of the coil. In the case of dual circuit units,the model number is based on the combined capacityof both coils. Fan Assembly

    For outdoor applications the condenser is equippedwith high efficiency axial type, impeller fan(s). Thequantity of fans varies depending upon the capacity ofthe unit. The fan(s) utilize corrosion resistant, multi-blade impellers designed for high aerodynamicefficiency which results in lower power consumption,lower noise levels and longer life. Each fan utilizes adirect driven motor with maintenance free bearings.The fan motors are internally protected from overload. Electric Box

    The electrical components are protected in a weatherresistant enclosure located at the header end of theunit. The electric box has a removable front accesspanel which is safety interlocked with the servicedisconnect switch, preventing the panel from beingremoved when the switch is in the On position. Theswitch must be turned Off to gain access to theelectrical components.

    Figure 1- Typical Layout








  • (Sept, 2007)

    SCS Installation, Operation & Maintenance Manual

    Air Technology Systems, Inc.


    2-Year Standard Limited Warranty:

    Stulz Air Technology Systems, Inc., warrants to the original buyer of its products that thegoods are free from defects in material and workmanship. Stulz Air Technology Systems,Inc.s obligation under this warranty is to repair or replace, at its option, free of charge tothe customer, any part or parts which are determined by Stulz Air Technology Systems be defective for a period of 24 months from date of shipment when a completed start-upform has been submitted to Stulz Air Technology Systems, Inc. within 90 days fromshipment. In the event that a completed start-up form is not received by Stulz Air Technol-ogy Systems, Inc. within 90 days from shipment, the companys obligation will be for aperiod of 12 months from date of shipment. Parts repaired or replaced under this warrantyare shipped FOB Factory, and warranted for the balance of the original warranty period orfor 90 days from the date of installation, whichever is greater.

    Stulz Air Technology Systems, Inc.s warranty does not cover failures caused by improperinstallation, abuse, misuse, misapplication, improper or lack of maintenance, negligence,accident, normal deterioration (including wear and tear), or the use of improper parts or improperrepair.

    Purchasers remedies are limited to replacement or repair of non-conforming materials inaccordance with the written warranty. This warranty does not include costs for transportation,costs for removal or reinstallation of equipment or labor for repairs or replacement made in thefield.

    If any sample was shown to the buyer, such sample was used merely to illustrate the generaltype and quality of the product, and not to represent that the equipment would necessarilyconform to the sample.

    This is the only warranty given by the seller, and such warranty is only given to buyers forcommercial or industrial purposes. This warranty is not enforceable until the invoice(s) is paidin full.


    1.3 Product Warranty

    SATS offers a two year standard limited warranty as stated below.

  • (Sept, 2007)

    SCS Installation, Operation & Maintenance Manual

    Air Technology Systems, Inc.


    1.4 Safety

    1.4.1 General

    Stulz Air Technology Systems, Inc. uses NOTESalong with CAUTION and WARNING symbols through-out this manual to draw your attention to importantoperational and safety information.

    A bold text NOTE marks a short message in theinformation to alert you to an important detail.

    A bold text CAUTION safety alert appears withinformation that is important for protecting yourequipment and performance. Be especially careful toread and follow all cautions that apply to your applica-tion.

    A bold text WARNING safety alert appears withinformation that is important for protecting you fromharm and the equipment from damage. Pay veryclose attention to all warnings that apply to yourapplication.

    A safety alert symbol accompanies a generalWARNING or CAUTION safety statement.

    A safety alert symbol accompanies an electricalshock hazard WARNING or CAUTION safety state-ment.

    1.4.2 Safety Summary

    The following statements are general guidelinesfollowed by warnings and cautions applicablethroughout the manual.

    Prior to performing any installation, operation, mainte-nance or troubleshooting procedure read and under-stand all instructions, recommendations and guide-lines contained within this manual.

    CAUTION All maintenance and/or repairs must beperformed by a journeyman, refrigerationmechanic or an air conditioning technician.

    CAUTION Never lift any component in excess of 35 poundswithout help. If a lifting device is used to move aunit, ensure it is capable of supporting the unit.

    CAUTION Do not allow the unit to swing while suspendedfrom a lifting device. Failure to observe this warn-ing may result in injury to personnel and dam-age to the equipment.

    CAUTION Do not allow anyone under the equipment sus-pended from a lifting sling.

    WARNING High voltage is used in the operation of thisequipment. Death on contact may result ifpersonnel fail to observe safety precautions.

    CAUTION When working on electrical equipment, removeall jewelry, watches, rings, etc. Keep one handaway from the equipment to reduce the hazardof current flowing through vital organs of the body.

    CAUTION Always disconnect the main power supply tothe equipment at the main power disconnectswitch before beginning work on the equipment.A lock-out tag-out procedure should be followedto ensure that power is not inadvertently recon-nected.

    CAUTION Equipment may contain components subject toElectrostatic Discharge (ESD). Before attempt-ing to mount or service these electronic devices,ensure you have no charge built up by touchinga ground source. When possible, use a wrist-grounding strap when working on or near elec-tronic devices.

    CAUTIONNever work on electrical equipment unless an-other person who is familiar with the operationand hazards of the equipment and competent inadministering first aid is nearby.

  • (Sept, 2007)

    SCS Installation, Operation & Maintenance Manual

    Air Technology Systems, Inc.


    CAUTION All personnel working on or near equipmentshould be familiar with hazards associated withelectrical maintenance. Safety placards/stick-ers have been placed on the unit to call atten-tion to all personal and equipment damage haz-ard areas.

    CAUTION Ensure the unit is properly phased. Improperphasing can cause severe damage to the com-pressor.

    WARNING Refrigerant (R22 or R407C) is used with thisequipment. Death or serious injury may result ifpersonnel fail to observe proper safety precau-tions. Great care must be exercised to preventcontact of liquid refrigerant or refrigerant gas, dis-charged under pressure, with any part of thebody. The extremely low temperature resultingfrom the rapid expansion of liquid refrigerant orpressurized gas can cause sudden and irrevers-ible tissue damage.

    As a minimum, all personnel should wear ther-mal protective gloves and face-shield/goggleswhen working with refrigerant. Application of ex-cessive heat to any component will cause ex-treme pressure and may result in a rupture.

    Exposure of refrigerant to an open flame or avery hot surface will cause a chemical reactionthat will form carbonyl chloride (hydrochloric/hy-drofluoric acid); a highly poisonous and corro-sive gas commonly referred to as PHOSGENE.In its natural state, refrigerant is a colorless, odor-less vapor with no toxic characteristics. It isheavier than air and will disperse rapidly in awell-ventilated area. In an unventilated area, itpresents a danger as a suffocant.

    Always refer to the manufacturer's MSDS pro-vided with the unit.

    WARNING Avoid skin contact or inhaling fumes from anyacid formed by burn out of oil and refrigerant.Wear gas mask if area is not thoroughly venti-lated. Wear protective goggles or glasses toprotect eyes. Wear rubber gloves to protecthands. Use care to avoid spilling compressorburnout sludge. If sludge is spilled, clean areathoroughly.

    WARNING When performing soldering or de-soldering op-erations, make certain the refrigeration systemis fully recovered and purged and dry nitrogen isflowing through the system at the rate of notless than 1-2 CFM (.03 - .06 M/minute).

    CAUTION Certain maintenance or cleaning proceduresmay call for the use and handling of chemicals,solvents, or cleansers. Always refer to themanufacturer's Material Safety Data Sheet(MSDS) prior to using these materials. Cleanparts in a well-ventilated area. Avoid inhalationof solvent fumes and prolonged exposure of skinto cleaning solvents. Wash exposed skin thor-oughly after contact with solvents.

    CAUTION Do not use cleaning solvents near open flame orexcessive heat. Wear eye protection when blow-ing solvent from parts. The pressure-wash shouldnot exceed 30 psig. Solvent solutions should bedisposed of in accordance with local and stateregulatory statutes.

  • (Sept, 2007)

    SCS Installation, Operation & Maintenance Manual

    Air Technology Systems, Inc.



    2.1 Receiving the Equipment

    Your system has been tested and inspected prior toshipment. To ensure that your equipment has beenreceived in excellent condition, make a visual inspec-tion of the equipment immediately upon delivery.Carefully remove the shipping container and allprotective packaging. Open the electric box andthoroughly inspect the unit for any signs of transit-incurred damage. If there is shipping damage, it mustbe noted on the freight carrier's delivery forms BE-FORE signing for the equipment. Any freight claimsMUST be done through the freight carrier. SATS shipsall equipment FOB factory. SATS is not liable for anyequipment damage while in transit. SATS can assist inthe claim filing process with the freight carrier. Shouldany damage be present, notify the SATS ProductSupport Group prior to attempting any repairs. Refer tosection five of this manual for instructions.

    Check the equipment against the packing slip to see ifthe shipment is complete. Report all discrepancies toappropriate authority.

    A Data Package has been sent with your unit. Itcontains this manual, system drawings, applicableMSDSs and other applicable instructions based onthe configuration and options of your unit. The datapackage has been placed in your unit in a clear plasticenvelope. These documents need to be kept with theunit for future reference.

    2.2 Site Preparation

    SATS Air Cooled Condensers are designed with easyservice access in mind. Install the condenser in asecure location where the unit cannot be tamperedwith and the main power disconnect switch cannot beinadvertently turned off. Allow access to the unit forroutine operation, servicing and for necessary mainte-nance. The components on outdoor condensers areaccessed through the top by removing the fan assem-bly panel. The electric box is accessed at the headerend of the unit. Locate the unit where the fan(s) are notlikely to draw dirt and debris into the coil fins. Refer tothe installation drawing provided with your unit for thedimensions.


    Working clearance requirements need to be es-tablished prior to mounting the unit. Refer to lo-cal and national electrical codes.

    CAUTION The condenser must be kept level to operateproperly.

    2.3 Rigging

    The unit must be kept level in a vertical position. Movethe unit with a suitable device such as a forklift orattach an overhead lifting sling. The unit may be liftedwith an overhead sling attached to the top of themounting support legs. Use an appropriate liftingdevice that has the capacity to safely handle theweight of the equipment. A weight table is provided onthe installation drawing provided with your unit. If usingan overhead lifting device, utilize spreader bars thatexceed the cabinet width so as to avoid crushing thesides of the unit. Remote condensers are shipped on askid to facilitate moving prior to installation. Unitsshould always be stored in a dry location prior toinstallation.

    CAUTION Take care not to damage the exposed coil finson the underside of the cabinet when movingthe unit.

    2.4 Mounting/Placement

    Outdoor, air cooled condensers are designed formounting to a flat surface. Condensers must not belocated in the vicinity of steam, hot air or fume ex-hausts. Avoid overhead obstructions. Ensure the unitis not located above or near noise sensitive areas. Ifpossible, make use of terrain features such as treesand buildings to provide a shaded location. This willminimize the solar load on the unit. Avoid ground levelsites that are accessible to the public.

    Ensure the mounting location is capable of supportingthe weight of the equipment. Refer to the installationdrawing for the non-charged system weight. Wheninstalling the unit on a roof, ensure the weight isadequately distributed to the load bearing points. Forground mounted units, install a concrete slab asshown in Figure 2. The slab should extend below thefrost line and be at least 2 inches higher than thesurrounding grade. The slab should extend at least 2beyond the outer profile of the condenser on all sides.

  • (Sept, 2007)

    SCS Installation, Operation & Maintenance Manual

    Air Technology Systems, Inc.


    walls or the pit. A stack may be used, if necessary, toextend the air discharge. The height of the extensionmust not exceed 10 feet.

    2.5 Piping Connections

    Split air cooled systems require a field installed copperdischarge line and copper liquid line between thecondenser and the evaporator. Dual circuit condenserswill require 2 sets of piping. Refer to the refrigerationdiagram provided with your unit for piping details.

    All refrigerant piping should be installed with hightemperature soldered joints. Use standard refrigerationpractices for piping supports, leak testing, dehydrationand charging of the refrigeration circuits. The refriger-ant piping should be isolated from the building by theuse of vibration isolating supports. To prevent tubedamage when sealing openings in walls and to reducevibration transmission, use a soft flexible material topack around the tubing.

    Clear all pipe connections of debris and prepare theconnections for soldering. Use only "L" or "K" graderefrigerant copper tubing. Be careful not to allowsolder/piping debris to get inside refrigerant lines.Silver solder containing a minimum of 15% silver isrecommended. Dry nitrogen should be flowing throughthe tubing while soldering at a rate of not less than 1-2CFM (.03 - .06 M3/minute).

    Refrigerant lines for split systems must be sizedaccording to the piping distance between the evapora-tor and the condenser. Each valve, fitting and bend inthe refrigerant line must be considered in this calcula-tion. Refer to the following table for standard equivalentlengths, in feet, of straight pipe.

    Insert vibration isolators between the unit and thebase as shown in Figure 2 to reduce the vibrationtransmitted to the mounting surface. Secure the unitwith fasteners, (field supplied by others), to preventthe system from moving during operation.

    The clearance around the unit to the nearest wall orobstruction should be at least 1 times (1x) the unitswidth to ensure adequate airflow to the coil(s) (seeFigures 3 & 4). Space multiple units at least 2 times(2x) the units width when placing them side by side.Ensure hot exhaust air is not directed toward the airinlet of an adjacent unit. When placing units end toend, allow at least 4 feet of space between units.Avoid areas where heavy snow will accumulate at airinlet and outlet openings.

    If the unit(s) are surrounded by three walls or, if theyare located in a pit, space them at least 2 times (2x)the units width from the nearest walls (see Figure 4).The top of the unit must be equal to the height of the










    Figure 2- Ground Mounting

    1x WIDTH




    Figure 3- Side Clearance



    10 FT. MAX.STACK


    Figure 4- Walled Areas or Pits

  • (Sept, 2007)

    SCS Installation, Operation & Maintenance Manual

    Air Technology Systems, Inc.


    2.5.1 Refrigerant Pipe Sizing

    The following general guidelines may be used to assistin determining the size of the refrigerant lines betweenthe evaporator section and the remote air cooledcondenser.

    Refer to the installation manual provided with the A/Csystem for tables showing the recommended dis-charge and liquid line pipe sizes for the A/C systemyou are installing. Things to consider when sizingrefrigerant piping are the varying BTU capacities ofindoor evaporators and the equivalent length of pipeneeded between the remote condenser and theevaporator. If the pressure drop is too high, the capac-ity of the compressor decreases and the powerrequired increases. An excessive refrigerant charge willbe used if the volume of the piping is too large.


    The size of the equipment pipe connections doesnot indicate the size of the refrigerant lines to beused. In cases where the pipe size doesnt matchthe size of the connection, reducing fittings mustbe used to transition between the connectionand the pipe. Discharge Lines

    If the condenser is installed above the evaporator, thedischarge line should include a shallow P-trap at thelowest point in the piping (see Figure 5). The highestpoint in the discharge line should be above the con-denser coil. Additionally, shallow P-traps must beincluded in the discharge line for every 20 feet of verticalrise. All horizontal refrigerant lines should be pitched inthe direction of flow at least 1/4" per 10 feet. Invertedtraps should be installed at the condenser to preventrefrigerant migration to the evaporator during off cycles.

    Figure 5- Piping Installation













    Its important that the discharge line is sized with acertain degree of pressure drop. This will ensure therefrigerant flows at a velocity high enough for therefrigerant vapor to carry the oil with it to the con-denser and to prevent the oil from returning to thecompressor.

    Compressor discharge pressure is always higher thancondensing pressure due to the line pressure drop.The line pressure drop also causes a change in therefrigerant saturation temperature. The discharge lineneeds to be sized so the pressure drop wont cause acorresponding change in saturation temperatureexceeding 2F.

    Discharge piping is typically sized for a total linepressure drop of 5 psi (+/- 50%), which results in onlya 1/2% to 1% reduction in compressor capacity.Pressure drops greater than 10 psi will impair systemperformance.

    Figure 5 depicts a typical piping diagram when thecondenser is located at a higher level than the indoorevaporator. In this situation, its especially important tosize the discharge line properly. If the discharge line issized correctly for full load operation, the velocity of

    Equivalent Length (ft) of Straight Pipe

    OD (In.) Globe Angle 90 45 Tee TeeLine Size Valve Valve Elbow Elbow Line Branch

    1/2 9.0 5.0 0.9 0.4 0.6 2.0

    5/8 12 6.0 1.0 0.5 0.8 2.5

    7/8 15 8.0 1.5 0.7 1.0 3.5

    1-1/8 22 12 1.8 0.9 1.5 4.5

    1-3/8 28 15 2.4 1.2 1.8 6.0

    1-5/8 35 17 2.8 1.4 2.0 7.0

    2-1/8 45 22 3.9 1.8 3.0 10

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    SCS Installation, Operation & Maintenance Manual

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    the gas may be too low during minimum load condi-tions to carry the refrigerant oil up the discharge line tothe condenser coil. Decreasing the size of the dis-charge line will increase the refrigerant velocity;however, it will also restrict the flow of refrigerant at fullload conditions creating an excessive refrigerantpressure drop.

    To remedy this, dual risers may be used as shown inFigure 6. Discharge riser #1 should be sized to allowthe refrigerant gas to flow at a sufficient velocity duringminimum load conditions to carry the oil. Riser #2should be sized in such way that the inside diameterof riser #1 and #2 will together have enough combinedarea to allow for a flow velocity suitable to carry therefrigerant oil to the condenser during peak loadconditions. Use a trap between the 2 risers so riser #2will be sealed off when the trap fills with oil duringpartial load operation, thus diverting the flow of refriger-ant to riser #1.

    *Consult Factory

    Line Liquid Line Discharge Line

    Size 100F 120F condensing

    O.D. R22 R407C R22 R407C

    1/2 7.12 * 0.3 *5/8 11.3 * 0.3 *7/8 23.4 * 0.5 *1 1/8 40.0 * 0.9 *1 3/8 60.5 * 1.3 *1 5/8 85.0 * 1.8 *2 1/8 150.0 * 3.3 * Liquid Line

    The velocity of refrigerant in the liquid line is lesscritical because liquid refrigerant and oil mix com-pletely. The main concern when sizing the liquid line isto maintain a solid liquid head of liquid refrigerantentering the expansion valve. If the refrigerant pressurefalls below its saturation temperature, a portion of theliquid refrigerant changes into vapor. Liquid refrigerantis sub-cooled slightly below its saturation tempera-ture. Sub-cooling must be sufficient to allow thenecessary pressure drop without approaching asaturation condition where gas flashing could occur.Under normal operation, the refrigerant is sufficientlycooled as it leaves the condenser to allow for normalline pressure drops. Liquid line size is selected basedon a pressure drop equivalent to 2F sub-cooling.


    When a receiver is used with the equipment, it shouldbe below the level of the condenser. The liquid linefrom the condenser to the receiver should be liberallysized to allow the refrigerant to freely flow from thecondenser to the receiver. The refrigerant line pressuredrop must not exceed 14 psig across the condenserand the interconnecting piping to the evaporator andcondenser sections. Weight of Refrigerant(Lbs./100 Ft. of Type L Tubing)

    The following table assists in determining the weight ofthe refrigerant by various line sizes.













    RISER #2

    RISER #1

    Figure 6- Dual Riser Piping

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    SCS Installation, Operation & Maintenance Manual

    Air Technology Systems, Inc.


    2.6 Utility Connections

    2.6.1 Main Power And Control Wiring

    Systems equipped with a remote condenser requirefield wiring between the condenser and the indoorevaporator section (see Figure 7). The condenser isprovided with main power and control terminal posi-tions for connection of the field wiring (supplied byothers). It is important to identify the options that werepurchased with the unit in order to confirm which fieldconnections are required. Refer to the electricaldrawing supplied with the unit to determine the totalnumber of interconnecting conductors required for yoursystem.

    Verify that the main power supply coincides with thevoltage, phase and frequency information specified onthe system nameplate. The supply voltage measuredat the unit must be within 10% of the voltage speci-fied on the nameplate (see Figure 8). The nameplatealso provides the full load amps (FLA), the current thatthe unit will draw under full design load, the minimumcircuit ampacity (MCA) for wire sizing, and the maxi-mum fuse or HACR (Heating, Air Conditioning, Refrig-eration) breaker size (MAX FUSE/CKT BKR) for circuitprotection. The unit's nameplate is located inside theelectrical box.

    Pilot hole openings for the conduit are located in thebottom of the electric box. A label stating "MAINPOWER INPUT" is in close proximity. The main powerwires are terminated at the line side of the servicedisconnect switch located within the electric box. Aseparate equipment ground lug is provided within theelectrical box for termination of the earth ground wire.

    The installer must also wire control conductors fromthe terminal board within the electric box to thesystem controller. The number of control conductorsneeded will vary depending on the type of controlmethod being used with your equipment. Refer to theelectrical drawing supplied with your unit to determinethe correct quantity of control conductors needed andfor the proper wire terminations.

    Figure 7- Field Wiring


    WITH NFPA 70, N.E.C.)








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    Figure 8- Sample Nameplate

    WARNINGHigh voltage is used in the operation of thisequipment. Death on contact may result ifpersonnel fail to observe safety precautions.

    WARNINGVerify power is turned off before making connec-tions to the equipment.


    All wiring must conform to local and national elec-trical code requirements. Use of copper conduc-tors only is required. Wiring terminations maybecome loose during transit of the equipment;therefore, it is required to verify that all wiringterminations are secure.

    It is important to note that the control transformersupplied with the equipment is sized and selectedbased upon the expected load for the system.


    Do not connect any additional loads to the sys-tem control transformer. Connecting additionalloads to the factory supplied control transformermay result in overloading of the transformer.

    CAUTION Improper wire connections will result in the re-verse rotation of the fan. To correct this prob-lem, exchange any two of the incoming mainpower wires at the main power circuit breaker.Do NOT rewire the unit's individual components.

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    2.7 System Settings and Adjustments

    Refrigerant charging procedures vary depending on thetype of refrigerant used in the unit. Before charging,check the unit nameplate to confirm the refrigeranttype. If the unit operates with R22 refrigerant seesection 2.7.1. If R407C is used, see section 2.7.2.

    2.7.1 R22 Refrigerant Charging Procedures


    Refrigerant charging must be performed by a jour-neyman, refrigeration mechanic or an air condi-tioning technician. Remote Air-Cooled Split Systems

    Follow the step by step instructions below to chargesystems using R22 refrigerant.


    1. Once all connections have been made, pressurizethe system to 150 psig with dry nitrogen. Leaksmay be detected by observing the standingpressure.

    2. After ensuring there are no leaks, relieve pressureand evacuate the system. Pull a vacuum of 50microns or less using the suction and dischargeservice ports and the service port of the receiver (ifapplicable). Hold the vacuum for at least 2 hours.Ensure no portion of system has been isolatedfrom the evacuation process (liquid, suction ordischarge lines).

    CAUTION A proper vacuum must be drawn on the refriger-ant system prior to charging. If this is not donethe refrigerant will combine with moisture in thepipes to form an acid that will eventually lead tocompressor failure.

    FINE TUNING THE SYSTEM CHARGE 0F Fan Cycling and -20F VariableSpeed Control

    The following instructions are for charging systemswith condenser fan cycling or variable speed controlusing R22 refrigerant.

    1. Bleed air from hoses and "break" the systemvacuum by supplying R22 vapor. Supply R-22vapor until the pressure is raised to about 50psig. This small holding charge allows the lowpressure switch to make throughout the pro-cess of fine tuning the system charge

    WARNING Do not add liquid R22 refrigerant to the suctionside of the system.

    2. Start the system and use the controller to lowerthe room temperature set-point 3-5F below actualroom temperature. This will ensure the coolingmode stays on during the charging procedure.

    CAUTION An adequate heat load must be supplied to theunit to ensure a proper charge.

    3. Supply R22 vapor to the suction port until theliquid line sight glass is cleared of all bubbles.

    4. After the unit has stabilized, the liquid line sightglass should be clear and the discharge pressureshould be a minimum of 200 psig. A superheatreading should be taken near the feeler bulb fromthe thermal expansion valve, with the temperature-measuring device being well insulated. The idealsuperheat temperature is 12-15F. Maximumallowable superheat temperature is 20F.

    5. A sub-cooling reading should be taken on theoutput side of the condenser, with the temperaturemeasuring device being well insulated. The sub-cooling temperature should be approximately 10-20F.


    Under cold climate conditions it is recommendedto do the following:

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    6. Block off the intake air to the condenser coil withcardboard until a constant discharge pressure(225-280 psig) can be obtained. This will lower thepossibility of overcharging and avoid the occa-sional bubbles that may appear in the sight glassduring fan cycling. (For units with fan cycling only.)

    CAUTION When charging is complete, remove theblockage to the air intake of the condenser coil.

    7. Fill out applicable sections of Warranty Registra-tion and Start-Up Checklist. -30F Flooded Head Pressure Control

    The following instructions are for charging systems withflooded head pressure control using R22 refrigerant.

    1. Bleed air from hoses and "break" the systemvacuum by supplying R22 liquid to the service valveof the receiver until the receiver is full. Then supplyR22 vapor to the suction port until the pressure israised to about 50 psig (low pressure switchmakes).

    2. Start the system and use the controller to lowerthe temperature set-point 3-5F below roomtemperature. This will ensure cooling remains onduring charging procedure.

    CAUTION An adequate heat load must be supplied to theunit to ensure a proper charge.

    3. After starting the system, immediately supplyR22 vapor to the suction port until the liquid linesight glass has cleared of all bubbles.

    4. Raise the discharge pressure to 300-325 psig andhold it constant by blocking the air intake of thecondenser.

    5. Once the discharge pressure has stabilized for 5 to10 minutes, additional refrigerant R22 vapor mustbe added to the suction port until the "float ball" inthe level indicator of the receiver begins to float.

    CAUTION Remove the blockage to the air intake of thecondenser.

    6. Take a superheat temperature reading near thefeeler bulb from the thermal expansion valve. Theideal superheat temperature is 12-15F. Maximumallowable superheat temperature is 20F.

    7. Fill out applicable sections of the WarrantyRegistration and Start-Up Checklist.

    2.7.2 R407C Refrigerant Charging ProceduresR407C is a blended refrigerant recognized for beingsafer for the environment. R407C refrigerant containsno chlorine, the component in HCFCs that destroythe earths ozone layer. However, the same careshould be taken to prevent leakage because R407Ccan contribute to the greenhouse effect if released.

    Refrigerants that are multi-component blends havecomponent parts with different volatilities that result ina change in composition and saturation temperatureas evaporation and condensation occur. Typically, thecomposition of R407C vapor is different than that ofR407C liquid within a contained system. The compo-sition of liquid R407C refrigerant remains relativelyconstant, however, the refrigerant vapor tends toseparate into its component parts even when circulat-ing.

    When charging a system using a blended refrigerant,it is essential that the composition of the refrigerant ismaintained. To ensure correct composition, introduceR407C into the system in liquid form rather than vaporform. Cylinders which are not provided with dip tubesshould be inverted to allow only liquid refrigerant tocharge the system. Keeping the temperature of thecylinder below 85F will help to maintain the correctrefrigerant composition while the cylinder is emptied.

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    CAUTION POE oil is used in systems with R407Crefrigerant. POE oil quickly absorbs moisturewhen exposed to air. High POE oil moisturelevels react with refrigerant to form acid, whichresults in system contamination. Keep theentire system sealed as much as possibleand minimize exposure of the POE oil tooutside air. Familiarize yourself with thecharging procedures discussed in section2.7.1 of this manual. Instead of adding R22vapor to the suction port as described underPreparing System For Charging, the initialcharge will be performed by introducingR407C liquid to the discharge side of thecompressor.


    1. With all the system piping connections made,perform a dry nitrogen leak detection test on thesystem. Using dry nitrogen only, pressurize thesystem to 150 psig. Since there is no refrigerantin the system to detect, leaks may be detectedby observing the standing pressure.

    2. After ensuring there are no leaks, evacuate thesystem to 50 microns and hold the vacuum for 2hours.

    3. Break the vacuum by supplying R407C liquid tothe discharge port near the compressor until thepressure is raised to about 50 psig. This smallholding charge allows the low pressure switch tomake through the process of fine tuning thesystem charge.


    4. Disconnect the refrigerant cylinder from thedischarge side of the compressor and connect itto the suction side.

    5. Start the system and use the controller to lowerthe room temperature setpoint 3-5F below actualroom temperature, ensuring cooling remains onas the unit is charged.

    6. Allow the discharge pressure to rise to 225-280psig and hold it constant. On cool days it may benecessary to restrict the airflow across thecondenser coil to raise the pressure.

    7. Slowly meter R407C liquid refrigerant through thesuction side while watching the sight glass to clearof bubbles.

    CAUTION Add liquid refrigerant slowly to prevent the refrigerantoil from washing out of the compressor.

    8. Take a superheat temperature reading near thefeeler bulb from the thermal expansion valve, withthe temperature measuring device being wellinsulated. The ideal superheat temperature is 12-15F. Maximum allowable superheat temperatureis 20F.

    9. While monitoring the sight glass, take a sub-cooling temperature reading on the output side ofthe condenser. The sub-cooling temperatureshould be 10-20F.

    10. If necessary, add liquid refrigerant to maintainadequate sub-cooling temperature. R407C Flooded Head Pressure Control

    In units with R407C refrigerant using flooded headpressure control, a receiver is provided to store therefrigerant during the time the condenser is not usingthe extra refrigerant charge. Once a clear sight glasshas been achieved, additional refrigerant must beadded to the receiver.

    A level indicator is located on the side of the receiverto assist the service technician in charging the airconditioning system. The proper charge can bedetermined by viewing the position of the float ballwhile the unit is running. If the float ball is positionedat the bottom of the sight indicator, additional refriger-ant charge is needed. When the float ball reachesthe top of the indicator, the unit is fully charged.

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    2.7.3 Head Pressure Controls Condenser Fan Cycling

    Used for outdoor installations where ambient condenser air inlet temperatures are 0F or higher, a condenser fancycling switch monitors refrigerant discharge pressure and turns on the condenser fan as required to maintainallowable condenser pressures. This is a high-pressure differential control switch with SPST contacts and anautomatic reset. The switch activates the condenser fan contactor to maintain condensing temperature when thedischarge pressure rises to 275 psig.

    Factory setting: Contacts close on a pressure rise to 275 psig and open at 210 psig. Setpoint range is 170 to 375psig. Differential is non-adjustable and set at 70 psi.

    On larger units with multiple fans, each fan is controlled with its own fan cycling switch. Fans are staged tooperate sequentially as discharge pressure rises. The primary fan, closest to the header, turns on 1st as describedabove. If pressure continues to rise, adjacent fan(s) are set to turn on sequentially in 10 psig increments with thefan located furthest from the header turning on last. Conversely, as discharge pressure drops, the fans drop outsequentially in reverse order. See for the fan cycling pressure control settings.

    Dual Circuit condensers require a fan cycling pressure control switch for each refrigeration circuit. The two controlswitches are adjusted to the same pressure setpoint and wired in parallel to operate a single fan. If either controlswitch senses a rise in pressure, the fan will turn on. On dual circuit units with multiple fans, operation of eachadditional fan requires two pressure control switches, (one for each refrigeration circuit). Each set of paralleledswitches will be set to the same pressure such that each adjacent fan begins operating sequentially in 10 psigincrements as the pressure rises. Variable Condenser Fan SpeedUsed for outdoor installations where ambient temperatures may fall to -20F, a variable speed condenser fanmotor control is used to maintain head pressure. The fan speed control is a continual modulation of the motorsspeed. The condenser fan speed controller monitors the refrigerant discharge pressure. As discharge pressurerises, the fan speed increases. The condenser fan speed varies as required to maintain allowable condenserpressures. The fan speed controller is set to maintain condensing pressure at 275 psig and requires no adjust-ment.

    When used on systems with multiple condenser fans, variable fan speed control is used only on the primary fanwhich is closest to the header. Additional fans use pressure fan cycling control, as described in Section,to assist the primary fan to maintain proper head pressure. Fan Cycling Pressure Control Settings

    Cut-In Cut-Out

    1st Fan 2nd Fan 3rd Fan

    Cut-In Cut-Out Cut-In Cut-Out

    275 psig 210 psig 285 psig 220 psig 295 psig 230 psig Variable Fan Speed Pressure Control Settings

    Range (psig)

    Normal Min. Max.

    1st Fan (Variable) 2nd Fan 3rd Fan

    Cut-In Cut-Out Cut-In Cut-Out

    275 210 275 285 psig 220 psig 295 psig 230 psig

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    2-11 Flooded Head Pressure Control

    Used for outdoor installations where ambient con-denser air inlet temperatures may fall to -30F, floodedhead pressure control is designed to maintain headpressure during the low ambient temperature condi-tions. A head pressure control valve and a receiver isused in the refrigeration circuit to back up liquidrefrigerant into the condenser coil. The head pressurecontrol valve is a 3-way modulating valve controlled bythe discharge pressure (see Figure 9). The headpressure control valve and the receiver are typicallylocated within the indoor evaporator unit.

    When the A/C unit begins to operate, the dischargepressure rises. When the pressure reaches 275 psig,the condenser fan is cycled on as described inSection If multiple fans are used, they willoperate by pressure fan cycling in 10 psig increments.

    When ambient temperature drops, the dischargepressure drops also. When the discharge pressuredrops to approximately 180 psig, the head pressurecontrol valve diverts discharge gas away from thecondenser to the receiver. Liquid flow from the con-denser is restricted, causing liquid to back up in thecondenser.

    Flooding the condenser reduces the area available forcondensing. The desired result is to increase thepressure into the condenser, maintaining a minimumdischarge pressure during low ambient operation thusensuring proper condensing temperature. The headpressure control valve requires no adjustment.

    This method of controlling head pressure allows thecondenser fan to run continuously. While the fan isrunning, the flooded head pressure control valvemodulates the amount of discharge gas entering thereceiver. As the pressure increases, the valve divertsmore discharge gas to the condenser, allowing moreliquid to flow from the condenser to the receiver.

    When using this method of head pressure regulationthere must be enough refrigerant in the system toensure adequate charge at the lowest expectedambient temperature in which the system will beoperating. A receiver is used to store the extra refriger-ant when the condenser is not using it.








    Figure 9- Flooded Head Pressure Control Diagram

    Indoor EvaporatorSection

    Remote Air-CooledCondenser

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    Pressure/Temperature Settings For R22 & R407C

    Normal Min. Max.

    Sub-cooling F 10 5 20

    Superheat F 15 10 20

    Condensing Temperature F 125 105 140

    Suction Pressure (psig) 70 58 84

    Fan Cycling Control- Fan On (psig) 275 265 285

    Fan Speed Control (psig) 275 - -

    2.8 Refrigerant Characteristics

    2.8.1 Pressure/Temperature Settings

    The following chart is provided to assist with thenormal settings of the system for R22 and R407Crefrigerant. Where applicable, minimum and maximumsettings are given along with normal operating pres-sures.

    2.8.2 Saturated Refrigerant Pressure Tables

    The following refrigerant vapor pressure tables areprovided for reference for R22 and R407C refrigerant.



    R22 Refrigerant

    Temp. Pressure (F) (psig)

    20 43.222 45.524 47.826 50.228 52.6

    30 55.132 57.734 60.436 63.138 65.9

    40 68.742 71.744 74.746 77.848 81.0

    50 84.255 92.760 10265 11170 122

    75 13280 14485 15690 16895 182

    100 196105 210110 226115 242120 260

    125 278130 296135 316140 337

    R407C Refrigerant

    Temp. Pressure (F) (psig)


    20 37.022 39.124 41.326 43.628 46.0

    30 48.432 50.934 53.536 56.238 58.9

    40 61.742 64.644 67.646 70.748 73.8

    50 77.1


    95 206100 222105 239110 257115 275

    120 294125 315130 336135 358140 381




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    2.8.4 Refrigerant Charge Correction Factors(Low Ambient Flooded Condenser)



    Temp F 30F 25F 20F 15F 10F 5F

    60 1.0 1.6 2.3 3.0 3.7 4.3 50 2.0 2.5 3.0 3.5 4.0 4.5 40 2.6 3.0 3.4 3.8 4.2 4.6 30 3.0 3.3 3.7 4.0 4.3 4.7 20 3.3 3.6 3.9 4.1 4.4 4.7 10 3.5 3.8 4.0 4.3 4.5 4.8 0 3.7 3.9 4.1 4.3 4.6 4.8

    -10 3.8 4.0 4.2 4.4 4.6 4.8 -20 3.9 4.1 4.3 4.5 4.6 4.8

    Design T.D.

    2.8.3 Standard Refrigerant Charge




    012 20 0.02 0.45 018 20 0.02 0.45

    024 20 0.05 0.90

    036 24 0.05 1.20

    060 24 0.08 1.95

    096 24 0.11 2.60

    120 24 0.16 3.80

    144 24 0.22 5.30

    192 36 0.17 6.10

    252 36 0.17 6.10

    276 36 0.25 9.10

    312 36 0.26 9.32

    447 36 0.35 12.43

    525 36 0.38 13.62

    597 36 0.38 13.62

    683 36 0.50 18.06

    Numberof FaceTubesAvailable

    Lbs. PerFace Tube

    Lbs. TotalFor Unit


    Lbs. PerFace Tube

    Lbs. TotalFor Unit


    Consult Factory for

    R407C RefrigerantCharge Weights

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    3.1 Operation

    For new installations, ensure the unit is ready tooperate by going through the Checklist for CompletedInstallation, located in Appendix A, prior to start-up.


    A Warranty Registration and Start-Up Checklistis provided with the unit data package. It shouldbe completed during start-up and sent to SATS.This checklist should be used as a guideline foritems that need to be confirmed during start-up.


    Start-up must be performed by an authorized jour-neyman, refrigeration mechanic or an air condi-tioning technician.

    3.2 Step by Step Start-Up Instructions

    1. Replace all equipment removed prior to performingstart-up checks.

    2. Apply power to the condenser at the main powerdisconnect switch.

    The refrigeration circuit must be tested at start-up.Refer to the separate controller operation instructionssent with your unit in the data package.

    3. Test cooling operation by adjusting the tempera-ture setpoint at the system controller. The com-pressor should come on and the suction lineshould gradually drop in temperature.

    4. Ensure the fan(s) are rotating correctly and freelywithout any unusual noise.

    3.3 Operational Description

    1. When used with a SATS indoor evaporator unit,the A/C system compressor starts, then thecondenser fan(s) start. Operation of the condenserfans is dependant on the head pressure controlmethod used. See the descriptions for headpressure controls in Section 2.7.3.

    2. Remote air cooled condensers may be configuredfor stand alone opereation. In this case the fansbegin operating when power is turned on.

    3. Refrigerant flowing from the evaporator in the formof a low pressure gas, enters the compressorwhere it is compressed into a high temperature,high pressure gas.

    4. The refrigerant then flows to the condenser coil.The high temperature, high-pressure gas from thecompressor is cooled by the flow of air through thecondenser coil and is condensed into a high-pressure liquid.

    5. For cold weather applications using flooded headpressure control, the low temperature high-pressure liquid refrigerant flows to a receiver. Thereceiver acts as a storage tank for the liquidrefrigerant that is not in circulation.

    6. The refrigerant flows through a liquid sight glass.This device indicates the presence of air, moistureand state of the refrigerant in the system.

    7. The low temperature high pressure liquid refriger-ant then flows to the evaporator where it removesheat and evaporates into a gas.

    8. The refrigerant gas is then drawn back to thecompressor and the cycle is repeated.

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    4.1 Periodic General Maintenance

    Systematic, periodic general maintenance of thecondenser is recommended for optimum systemperformance. General maintenance should include, butis not limited to the following: tightening electricalconnections, cleaning the interior of the unit, inspect-ing the units components visually.

    Use copies of the Periodic General MaintenanceChecklist in this manual (see Appendix A) to recordperiodic general maintenance inspections. Forassistance, contact the SATS Product Support Group.Ensure adherence to all safety statements whileperforming any type of maintenance.

    CAUTION All maintenance and/or repairs must beperformed by a journeyman, refrigerationmechanic or an air conditioning technician.

    WARNING Turn off power to the unit at the main power dis-connect switch unless you are performing teststhat require power. To prevent personal injury,stay clear of rotating components because au-tomatic controls may start them unexpectedly.With power and controls energized, the unit couldbegin operating automatically at any time.

    Hazardous voltage will still be present even withthe unit turned off at the controller. To isolate theunit for maintenance, always turn off power atthe main power disconnect switch prior to per-forming any service or repairs.

    This unit employs high voltage equipment withrotating components. Exercise extreme care toavoid accidents and ensure proper operation.

    4.1.1 General

    Maintenance access to the condenser is through theremovable fan assembly panel on top of the unit.Examine the areas around the air inlet and outlet grills,fans, motors and coils. Use a vacuum cleaner with asoft bristle brush to clean dirt from components.

    Clean the coil of all debris that will inhibit airflow. Thiscan be done with a vacuum cleaner, soft brush andcompressed air, or with a commercial coil cleaner.Check for bent or damaged coil fins and repair asnecessary. On outdoor units do not permit snow toaccumulate on or around the unit in the winter. Checkall refrigerant lines and capillaries for vibration isolationand support as necessary. Check all refrigerant linesfor signs of leaks.

    Examine all wiring for signs of chafing, looseconnections or other obvious damage. (Quarterly)

    Examine brackets, motor mounts and hardware forloose or missing parts or other damage. (Quarterly)

    Clean accumulations of dust and dirt from allinterior and exterior surfaces. (Quarterly)


    Fan motors have permanently sealed bearings,therefore, no lubrication is required.


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    Unit Fails to Start a. Incorrect phasing or voltage. Correct phase or voltage input.

    b. Power failure. Check power source, power input andfuses. Check control cables andconnections.

    c. Overload protection tripped. Check for cause of overload and repair.

    Control is Erratic Wiring improperly connected or Check wiring against schematicbroken. diagram.

    Condenser Head Pressure a. Low condenser airflow. (Indicated by Open air passages. Clean coil. Checktoo High excessive warm air leaving the condenser fan(s).

    condenser fan).

    b. Overcharge of refrigerant. Reclaim excess refrigerant from system.

    c. Condenser fan not operating. 1. Check main voltage power source tounit.

    2. Check fan motor, contactor, fan cyclingswitch or fan speed controller.

    3. Check pressure/temperature operatingswitches and motor. Replace as needed.

    d. Condenser pressure regulating Adjust to obtain correct pressure. valve setting too high.

    e. Non-condensable gas or air in the Reclaim system, pull 50 micron vacuumsystem. and recharge. Install new drier/strainer.

    Condenser Head Pressure a. Loss of refrigerant (indicated by Locate and repair leak. Rechargetoo Low bubbles in sight glass). system.

    b. Condenser fan controls not set Adjust or repair controls.properly.

    4.2 Troubleshooting

    Turn off all power to the unit before conducting anytroubleshooting procedures, unless the procedurespecifically requires the system to operate. Fortroubleshooting purposes, the system may be oper-ated with the electric box open by using a pair ofchannel lock pliers to turn the shaft of the main powerdisconnect switch to the On position. When theswitch is turned on, high voltage will be present inside

    the box. Exercise caution to prevent injury. Keephands, clothing and tools clear of the electricalterminals and rotating components. Ensure that yourfooting is stable at all times.

    WARNING This equipment should be serviced and repairedby a journeyman or a qualified refrigeration tech-nician only.

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    Head Pressure Too High a. Low condenser airflow. (Indicated by Open air passages. Clean coil. Checkexcessive warm air leaving the condenser fan(s).condenser fan).

    b. Air or other non-condensible gas Reclaim system and recharge. Install ain system new drier strainer.

    c. Overcharge of refrigerant. Reclaim excess refrigerant from system.

    d. Condenser fan not on. Check main voltage power source to unit.Check fan, contactor, fan cycling switch orfan speed controller.

    Erratic Fan Operation Dirty or blocked condenser coil. Clean coil or remove blockage.

    4.3 Field Service

    It may be necessary to perform repairs on the refrig-eration system. If field repairs are necessary, thefollowing procedures apply:


    Do not attempt to make repairs without theproper tools.

    4.3.1 Leak Detection

    Several methods can be used to detect a leak in therefrigeration system. The most modern and easiestmethod is to use an electronic leak detector. Followthe manufacturers directions and any leak can bequickly located. A second method is to use soapbubbles. Apply a solution of soapy water with a brushor sponge to the joints and connections in the refriger-ant lines. A leak in the lines will cause bubbles toform.


    Halogen leak detectors are ineffective withR407C refrigerant because unlike R22 refriger-ant, R407C does not contain chlorine.

    4.3.2 Leak Repair

    When a leak is located, properly reclaim the remainingrefrigerant charge before attempting repairs. Adjacentpiping must be thoroughly cleaned by removing all

    paint, dirt and oily film. Use wire brush, sandcloth orsandpaper and wipe the area with clean, dry cloths.Protect nearby parts from heat damage by wrappingwith water-soaked cloths

    4.3.3 Refrigerant Piping

    When replacing components within the cabinet, thefollowing consumable materials are recommended:Use Silfos alloy for copper-to-copper (piping dischargeor suction line repairs). Silver solder (Stay-Silv #45)and flux are to be used on copper-to-brass or copper-to-steel repairs. For liquid line repairs at the drier,strainer, sight glass, or expansion valve, use a 95% tinto 5% antimony solder with flux.

    When component replacement is complete, remove alltraces of flux. After any repair, pressure check thesystem, checking for leaks prior to recharging thesystem.

    4.3.4 Electrical System

    All electrical connections should be checked to besure that they are tight and properly made. Check allswitches, contactors and wiring. The contactor shouldbe examined and replaced if contacts are worn or pit-ted.

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    SATS provides its customers with a Product SupportGroup (PSG) which not only provides technical supportand parts but the following additional services, asrequested: performance evaluations, start-up assis-tance and training.

    5.1 Technical Support

    The SATS Product Support Group (PSG) is dedicatedto the prompt reply and solution to any problemencountered with a unit. Should a problem developthat cannot be resolved using this manual, you maycontact PSG at (240) 529-1399 Monday throughFriday from 8:00 a.m. to 5:00 p.m. EST. If a problemoccurs after business hours, dial the page number(301) 414-4514 and follow the steps below:

    1. Wait for the dial tone.

    2. Dial your telephone number (including area code).

    3. Press the pound (#) key.

    4. Wait for a busy signal.

    5. Hang up the telephone.

    One of our service technicians will return your call.When calling to obtain support, it is vital to have thefollowing information readily available, (information isfound on unit's nameplate):

    Unit Model Number (SCS-XXX-XXX)

    SATS Item Number (123456)

    Unit Serial Number (1234567)

    Description of Problem

    5.2 Obtaining Warranty Parts

    Warranty inquires are to be made through the ProductSupport Group (PSG) at (240) 529-1399 Mondaythrough Friday from 8:00 a.m. to 5:00 p.m. EST. Aservice technician at SATS will troubleshoot thesystem over the telephone with a field service techni-cian to determine the defect of the part. If it is deter-mined that the part may be defective a replacementpart will be sent UPS ground. If the customer requeststhat warranty part(s) be sent by any other method thanUPS ground the customer is responsible for theshipping charges. If you do not have established creditwith SATS you must provide a freight carrier accountnumber.

    A written (or faxed) purchase order is required onwarranty parts and must be received prior to 12:00p.m. for same day shipment. The purchase order mustcontain the following items:

    Purchase Order Number

    Date of Order

    SATS Stated Part Price (obtained from PSG)

    Customer Billing Address

    Shipping Address

    Customer's Telephone and Fax Numbers

    Contact Name

    Unit Model No., Serial No. & SATS Item No.

    The customer is responsible for the shipping costincurred for returning the defective part(s) back toSATS. Return of defective part(s) must be within 30days at which time an evaluation of the part(s) isconducted and if the part is found to have a manufac-turing defect a credit will be issued.

    When returning defective part(s) complete the ReturnMaterial Authorization Tag and the address labelreceived with the replacement part.

    See SATS Standard Warranty located in section oneof this manual.

    5.3 Obtaining Spare/Replacement Parts

    Spare and replacement parts requests are to be madethrough the Product Support Group (PSG) by fax (301)620-1396, telephone (240) 529-1399 or E-mail([email protected]). Quotes are given for specifiedlisted parts for a specific unit.

    SATS accepts Visa and MasterCard. SATS mayextend credit to its customers; a credit applicationmust be prepared and approved (this process couldtake one week).

    A 25% minimum restocking charge will be applied onreturned stocked parts that were sold as spare/replacement parts. If the returned part is not a stockeditem, a 50% restocking charge may be applied.Additionally a Return Material Authorization Number isrequired when returning parts. To receive credit forreturned repair/replacement parts, the parts must bereturned to SATS within 30 days of the purchase date.Spare part sales over 30 days old will be consideredfinal and the parts will remain the sole property of theordering party.

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    SCS Installation, Operation & Maintenance Manual

    Air Technology Systems, Inc.

    Stulz Air Technology Systems Inc.Frederick, Maryland USA 21704

    Telephone: (301) 620-2033 Facsimile: (301) 620-1396

    Checklist for Completed Installation

    Frederick, Maryland USA 21704

    Telephone: (301) 620-2033Facsimile: (301) 620-1396

    1 Proper clearances for service access havebeen maintained around equipment.

    2 Equipment is level and mounting fasteners aretight.

    3 Piping completed to refrigeration equipment.

    4 All field installed piping leak tested.

    5 Refrigerant charge added.

    6 Incoming line voltage matches equipmentnominal nameplated rating tolerances.

    7 Main power wiring connections to theequipment, including earth ground, have beenproperly installed.

    8 Customer supplied main power circuit breaker(HACR type) or fuses have proper ratings forequipment installed.

    9 Control wiring connections completed tocondenser.

    10 All wiring connections are tight.

    11 Foreign materials have been removed frominside and around all equipment installed(shipping materials, construction materials,tools, etc.).

    12 Inspect all piping connections for leaks duringinitial operation.


    Air Technology Systems, Inc.

    SCS Series Remote Air Cooled Condenser


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    SCS Installation, Operation & Maintenance Manual

    Air Technology Systems, Inc.

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    SCS Installation, Operation & Maintenance Manual

    Air Technology Systems, Inc.

    Frederick, Maryland USA 21704

    Telephone: (301) 620-2033Facsimile: (301) 620-1396


    Air Technology Systems, Inc.

    SCS Series Remote Air Cooled CondenserPeriodic General Maintenance Checks and Services Checklist

    Date: ____________________________ Prepared By: ___________________________

    Model Number: ____________________________ Serial Number: __________________________

    Item Number: ____________________________


    Area Around Condenser Unit Clean and Clear of Obstructions


    Check Refrigerant Charge (bubbles in sight-glass) Tighten Electrical Connections

    Check Suction & Discharge Pressure Ensure Motor Mounts are Secured

    Ensure Refrigerant Lines are Secured Clean Unit as Necessary


    Inspect Refrigerant System for Leaks and Corrosion

    Conduct a Complete Check of All Services ListedAbove and Clean Unit's Interior



    *** If factory assistance is required for any reason, provide the model number, serial number, and SATS itemnumber found on the unit nameplate. This will speed the process and ensure accuracy of information. ***

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    SCS Installation, Operation & Maintenance Manual

    Air Technology Systems, Inc.


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    SCS Installation, Operation & Maintenance Manual

    Air Technology Systems, Inc.

    Appendix B- Glossary

    Definition of Terms and Acronyms

    SATS - Stulz Air Technology Systems, Inc.

    BMS - Building Management System

    BTU/Hr - British Thermal Units Per Hour

    CNDCT - Conductor

    ESD - Electrostatic Discharge

    F - Degrees Fahrenheit

    FLA - Full Load Amps

    FOB - Freight on Board

    HACR - Heating, Air Conditioning, Refrigeration

    HP - Horse Power

    Hz - Hertz

    KVA - Kilo Volt Amps

    kW - Kilowatt

    LRA - Locked Rotor Amps

    MAX CKT Maximum Circuit BreakerBKR -

    MAX FUSE - Maximum Fuse

    MCA - Minimum Circuit Ampacity

    MSDS - Material Safety Data Sheet

    NEC - National Electric Code

    PH - Phase

    PSG - Product Support Group

    PSI - Pounds Per Square Inch

    PSIG - Pounds Per Square Inch Gauge

    RLA - Run Load Amps

    R-Value - Thermal Resistance

    R22 - Refrigerant (HCFC-22)

    R407C - Blended Refrigerant

    SPDT - Single Pole, Double Throw

    TEV - Thermal Expansion Valve

    V - Volt

    VAC - Volt, Alternating Current


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    SCS Installation, Operation & Maintenance Manual

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