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Installation, Operation and Maintenance Manual IOMM A-C Cond
Group: Chiller Part Number: 331376901 Effective: March 2007 Supersedes: IMM ACAQ-1
Air-Cooled Condensers
Model ACH 014 - 225 Model ACX 014 - 225 Model ACL 014 - 225 Capacities from 130 MBH to 2225 MBH R-22, R-134a
Table of Contents
Introduction........................................................................................................................3
Installation..........................................................................................................................3 Handling ....................................................................................................................................................3 Holding Charge..........................................................................................................................................4 Unit Location .............................................................................................................................................4 Sound/Vibration.........................................................................................................................................4 Rigging ......................................................................................................................................................5 Walls or Obstructions.................................................................................................................................5 Multiple Units ............................................................................................................................................6 Units in Pits................................................................................................................................................6 Decorative Fences......................................................................................................................................6
Dimensions..........................................................................................................................7
Refrigerant Piping .............................................................................................................8 Refrigerant Piping......................................................................................................................................8 Valves.........................................................................................................................................................8 Discharge Lines .........................................................................................................................................9 R-410A ......................................................................................................................................................9
Physical Data ....................................................................................................................10
Electrical Data..................................................................................................................11
Operation..........................................................................................................................18 Start-Up....................................................................................................................................................18 Discharge Gas Pulsation ..........................................................................................................................18 Discharge Pressure Control .....................................................................................................................18 Fan/Circuit Configuration........................................................................................................................19 Control options: .......................................................................................................................................19
Maintenance .....................................................................................................................26 Cleaning Instructions ...............................................................................................................................26
Manufactured in an ISO certified facility
©2007 McQuay International Illustrations cover the general appearance of McQuay International products at the time of publication and we reserve the right
to make changes in design and construction at anytime without notice.
2 IOMM A-C Cond
MODEL CODE AC H 100 A S
Introduction Carefully check each shipment against the bill of lading and account for all items. Report any shortage or damage to the delivering carrier.
On receipt of equipment, check the unit nameplate for correct electrical characteristics and working pressure. Refrigerants R-22, R-134a, R-407c have 450 psi; R-410a has 650 psi.
Be careful to prevent damage when uncrating. Heavy equipment should be left on unit’s shipping base until it has been moved to the final location.
This equipment must be installed in accordance with accepted industry standards. Failure to meet the following conditions may void the warranty:
1. System piping must be installed following industry standards for good piping practices. 2. Inert gas must be charged into piping during brazing/welding. 3. System must be thoroughly leak-checked and evacuated before initial charging. High
vacuum gauge capable of reading microns is mandatory. Dial indicating pressure gauges are not acceptable.
4. Power supply to system must meet the following conditions:
Voltage for 208/230 motors not less than 195 volts or more than 253 volts. All other voltages must be within 10% of nameplate ratings. Phase imbalance not to exceed 2%.
5. All controls and safety switch circuits properly connected per wiring diagram. 6. Factory installed wiring must not be changed without written factory approval. 7. Relief valves must meet all code requirements.
Installation
Handling Note: Installation and maintenance are to be performed only by qualified personnel who are familiar with local codes and regulations, and experienced with this type of equipment.
Avoid rough handling shock due to impact or dropping the unit. Do not push or pull unit.
Never allow any part of the unit to fall during unloading or moving, as this can result in serious damage.
! DANGER
Dangers indicate a hazardous situation which will result in death or serious injury if not avoided.
Improper lifting or moving of unit can result in property damage, severe personal injury or death. Follow rigging and moving instructions carefully.
Fan Rows/Circuits Air-cooled Condenser S=Single, D=Dual
Series: H, L, X Nominal Evaporator Tons Vintage
IOMM A-C Cond 3
Holding Charge The unit is shipped with a holding charge of dry nitrogen under nominal pressure.
Unit Location Units are designed for outdoor application and may be mounted on a roof or concrete slab (ground level installation). Install roof-mounted units on steel channels or an I-beam frame to support the unit above the roof. Use of vibration pads or isolators is recommended. The roof must be strong enough to support the operating weight of the unit.
For ground level installation, mount units on a one-piece concrete slab with footings extending below the frost line. Be certain concrete slabs are installed level and are properly supported to prevent settling.
Locate the condenser far enough away from any wall or other obstruction to provide sufficient clearance for air entrance. Do not attach ductwork to the coil inlet or fan outlet. Avoid air recirculation conditions that may be caused by sight screening, walls, etc. and keep unit fan discharge away from any building air intakes. Do not install unit where exhaust or ventilation equipment will affect entering air temperature or foul coils.
! WARNING
Warnings indicate potentially hazardous situations, which can result in property damage, severe personal injury, or death if not avoided.
This equipment may contain a substance which harms the public health and environment by destroying ozone in the upper atmosphere. Venting of
certain refrigerants to the atmosphere is illegal. Refrigerant recovery devices must be used when installing or servicing this product.
Sound/Vibration Install units away from occupied spaces, utility areas, corridors and auxiliary spaces to reduce the transmission of sound and vibration to occupied spaces. The refrigerant piping should be flexible enough to prevent the transmission of noise and vibration from the unit into the building. If the refrigerant lines are to be suspended from the structure of the building, use isolation hangers to prevent the transmission of vibration. Where piping passes through a wall, pack fiberglass and sealing compound around the lines to minimize vibration and retain flexibility. The unit must be secured in its final location. Holes are provided in the base runner for this purpose.
4 IOMM A-C Cond
Rigging Figure 1, Unit Rigging
Walls or Obstructions Locate the unit to ensure air can circulate freely and not be recirculated. For proper air flow and access, maintain the minimum distance from the unit to the wall as shown to the right. Increase this distance whenever possible. Leave maintenance room through access doors and panels. Overhead obstructions are not permitted. When enclosed by three walls, install unit as indicated for units in a pit.
ACH = 4 ft.ACL/ACX = 6 ft.
AIR FLOW
IOMM A-C Cond 5
Multiple Units
ACH = 6 ft.ACL/ACX = 8 ft.
AIR FLOW AIR FLOWFor units placed side by side, the minimum distance between units must be as shown to the right. If units are placed end to end, the minimum distance between units is 4 feet.
Units in Pits The top of the unit should not be more than two feet below top of the pit, and side distance should be as shown. If the top of the unit is not level with the top of pit, discharge cones or stacks must be used to raise discharge air to the top of the pit. This is a minimum requirement.
ACH = 4 ft.
ACL/ACX = 6 ft.
STACK(BY OTHERSIF SUPPLIED) 2 FT. MAX.
AIR FLOW
ACH = 4 ft.ACL/ACX = 6 ft.
Decorative Fences Fences must have 50% free area, with 1 foot undercut, at least the width of condenser minimum clearance, and must not exceed the top of unit. If these requirements are not met, unit must be installed as indicated for "Units in pits".
ACH = 3 ft.
ACL/ACX = 4 ft.
1 IN.MIN.
AIR FLOW
ACH = 3 ft
ACL/ACX = 4 ft.
6 IOMM A-C Cond
Dimensions
Note: All dimensions in inches unless otherwise indicated
IOMM A-C Cond 7
Refrigerant Piping Figure 2 illustrates a typical piping arrangement involving a remote condenser located at a higher elevation, as commonly encountered when the condenser is on a roof and the compressor and receiver are on grade level or in a basement equipment room. In this case, the design of the discharge line is very critical. If properly sized for full load condition, the gas velocity might be too low at reduced loads to carry oil up through the discharge line and condenser coil. Reducing the discharge line size would increase the gas velocity sufficiently at reduced load conditions; however, when operating at full load, the line would be greatly undersized, and thereby create an excessive refrigerant pressure drop. This condition can be overcome in one of the two following ways: 1. Size discharge line for the desired pressure drop at full load conditions and install an oil
separator at the bottom of the trap in the discharge line from the compressor. Figure 22. Use a double riser discharge line as shown in . Size line "A" to carry the oil at
minimum load conditions and size line "B" at full load conditions; both lines should have sufficient flow velocity to carry the oil to the condenser.
For more complete information, see the ASHRAE Handbook on Systems. Be aware of the following when fabricating piping:
All oil traps are to be as short in radius as possible. The trap may be fabricated using three 90- degree ells.
•
• •
Use pressure relief valves at the condenser to protect the coil. Use a drain line check valve when the condenser is at a lower temperature than the receiver.
Figure 2, Typical and Double Riser Discharge Piping Arrangement
Typical Piping Arrangement
COMPRESSORRECEIVER
CONDENSER
ReliefValve
LiquidLine
Trap
DischargeLine
Check Valve
Pitch
Pitch
Double Riser Discharge Piping Arrangement
Refrigerant Piping Install piping according to standard accepted refrigeration practice. See Table 1 and Table 2 for discharge and liquid drain line sizes for remote condenser connections. Use only refrigeration grade copper tubing and put dry nitrogen through lines while brazing.
! CAUTION Cautions indicate potentially hazardous situations which can result in personal injury or
equipment damage if not avoided. Do not use soft solder joints. Do not leave dehydrated piping or components open to
the atmosphere any longer than is absolutely necessary due to possible contamination and subsequent equipment damage.
Valves Equip major components with isolation valves and install a relief valve in the discharge line between the check valve and the condenser inlet isolation valve.
8 IOMM A-C Cond
IOMM A-C Cond 9
Discharge Lines Design discharge lines so that refrigerant pressure drop is minimized (high pressure losses cause increased compressor horsepower) and a sufficiently high gas velocity to carry oil through to the condenser coil and receiver at all loading conditions is maintained.
Table 1, Discharge Line Sizing Discharge Line Capacity in Evaporator Tons
R-22 R-134a R-407C R-410A Sat. Suction Temp. Sat. Suction Temp. Sat. Suction Temp Sat. Suction Temp
Line Size Type L Copper OD (in.) 0°F 20°F 40°F 0°F 20°F 40°F 0°F 20°F 40°F 0°F 20°F 40°F
1/2 0.8 0.8 0.8 0.5 0.6 0.6 0.8 0.9 0.9 1.3 1.3 1.3 5/8 1.5 1.6 1.6 1.0 1.1 1.1 1.5 1.6 1.7 2.4 2.4 2.5 7/8 4.0 4.1 4.2 2.7 2.8 2.9 4.1 4.2 4.4 6.2 6.4 6.5
1 1/8 8.0 8.3 8.5 5.4 5.7 6.0 8.2 8.5 8.9 12.5 12.9 13.2 1 3/8 14.0 14.4 14.8 9.4 9.9 10.4 14.2 114.8 15.4 21.7 22.4 22.9 1 5/8 22.1 22.7 23.4 14.9 16.7 16.4 22.5 23.4 24.3 34.3 35.3 36.1 2 1/8 45.7 47.1 48.5 30.8 32.4 34.0 46.5 48.4 50.3 70.8 72.8 74.6 2 5/8 80.4 82.9 85.4 54.4 57.2 59.9 82.0 85.4 88.7 124.5 128.3 131.2 3 1/8 128.2 132.2 136.2 86.7 91.2 95.5 130.5 136.0 141.2 198.4 204.3 209.0 3 5/8 190.3 196.2 202.1 129.0 135.0 142.0 193.3 201.4 209.2 293.9 302.7 309.6 4 1/8 267.8 276.1 284.4 181.0 191.0 200.0 272.6 284.0 295.0 413.8 426.1 435.9 Notes: 1. Source: ASHRAE Refrigeration Handbook: 2. Line sizes based on pressure drop equivalent to one degree F. per 100 equivalent feet 3. Values in Table are based on 105°F condensing temperature. Multiply Table capacities by the factors in
Table 2 for other condensing temperatures. 4. If the line is short, a smaller line size may be used and very long lines may require larger sizes.
Table 2, Condensing Temperature Correction Factor Discharge Line Condensing
Temperature R-22 R-404, R-507 90°F 0.88 0.91 100°F 0.95 -0.97 110°F 1.04 1.02 120°F 1.10 1.08 130°F 1.18 1.16
Table 3, Liquid Line Sizing Liquid Line Capacity
In Evaporator Tons at 100 FPM Velocity Line Size
Type L Copper OD (in.) R-22 R-134a R-407C R-410A
1/2 2.3 2.1 3.8 4.6 5/8 3.7 3.4 7.1 8.6 7/8 7.8 7.1 18.7 22.6
1 1/8 13.2 12.1 37.9 45.8 1 3/8 20.2 18.4 66.2 79.7 1 5/8 28.5 26.1 104.7 125.9 2 1/8 49.6 45.3 317.1 260.7 2 5/8 76.5 69.9 383.7 459.7 3 1/8 109.2 100.0 611.3 733.0 3 5/8 147.8 135.0 907.9 1087.5 4 1/8 192.1 175.0 1281.5 1530.2
R-410A R-410A can have discharge pressures well in excess of 450 psi and special care must be exercised in designing and installing refrigerant components and piping.
10 IOMM A-C Cond
Physical Data
Table 4, Physical Properties of Models ACH, ACL, ACX ACH ACL ACX Model
Size
No. of
RowFans /Row CFM Conn
(in.) Weight
(lbs) Fans /Row CFM Conn
(in.) Weight
(lbs) Fans /Row CFM Conn
(in.) Weight
(lbs)
014 S 1 1 9,900 1 3/8 330 1 8,400 1 3/8 330 1 7,600 1 3/8 330
016 S 1 1 9,500 1 3/8 360 1 8,000 1 3/8 360 1 7,300 1 3/8 360
020 S 1 2 20,500 1 3/8 580 2 17,500 1 3/8 580 2 15,900 1 3/8 580
025 S 1 2 19,800 1 5/8 630 2 16,700 1 5/8 630 2 15,200 1 5/8 630
030 S 1 2 19,000 2 1/8 680 2 16,100 2 1/8 680 2 14,700 2 1/8 680
040 S 1 3 29,700 2 1/8 930 3 25,100 2 1/8 930 3 22,900 2 1/8 930
050 S 1 3 28,500 2 1/8 1000 3 24,100 2 1/8 1000 3 22,000 2 1/8 1000
055 S 1 4 38,600 2 1/8 1210 4 32,800 2 1/8 1210 4 29,800 2 1/8 1210
060 S 1 4 37,000 2 5/8 1310 4 31,200 2 5/8 1310 4 28,400 2 5/8 1310
070 S 1 5 48,300 2 5/8 1510 5 41,000 2 5/8 1510 5 37,300 2 5/8 1510
080 S 1 5 46,200 2 5/8 1640 5 39,100 2 5/8 1640 5 35,500 2 5/8 1640
100 S 1 6 55,400 2 5/8 1950 6 46,900 2 5/8 1950 6 42,600 2 5/8 1950
110 S 1 7 64,700 (2)2 2240 7 54,700 (2)2 2240 7 49,700 (2)2 2240
040 D 2 2 41,000 (2)1 1240 2 35,000 (2)1 1240 2 31,700 (2)1 1240
050 D 2 2 39,600 (2)1 1340 2 33,500 (2)1 1340 2 30,500 (2)1 1340
060 D 2 2 38,100 (2)2 1440 2 32,100 (2)2 1440 2 29,300 (2)2 1440
080 D 2 3 59,400 (2)2 1990 3 50,200 (2)2 1990 3 45,700 (2)2 1990
100 D 2 3 57,100 (2)2 2140 3 48,200 (2)2 2140 3 44,000 (2)2 2140
110 D 2 4 77,200 (2)2 2630 4 65,600 (2)2 2630 4 59,700 (2)2 2630
130 D 2 4 73,900 (2)2 2830 4 62,500 (2)2 2830 4 56,800 (2)2 2830
140 D 2 5 96,500 (2)2 3290 5 82,000 (2)2 3290 5 74,600 (2)2 3290
160 D 2 5 92,400 (2)2 3540 5 78,100 (2)2 3540 5 71,000 (2)2 3540
200 D 2 6 110,90 (2)2 4230 6 93,700 (2)2 4230 6 85,200 (2)2 4230
225 D 2 7 129,40 (4)2 4910 7 109,30 (4)2 4910 7 99,400 (4)2 4910
IOMM A-C Cond 11
Electrical Data Install all electrical wiring according to the National Electrical Code, local codes and regulations. Use copper conductors only. All standard motors have internal inherent overload protectors, allowing contactors to be used instead of starters requiring thermal protectors.
! WARNING Warnings indicate potentially hazardous situations, which can result in
property damage, severe personal injury, or death if not avoided.
There may be more than one source of electrical current in this unit. Do not service before disconnecting all power supplies.
All condensers are furnished with either single-phase or three-phase fan motors, which are identified by the unit dataplate. Electrical leads from each motor terminate at the unit junction box. Field connections must be made from these leads in accordance with local, state and national codes. The motors are wired into a common junction box. Where fan cycling is furnished and factory installed, the motors are completely wired through the control and to the contactors. Check motors for proper rotation and be sure motor voltage and control voltage agree with electric services furnished.
Table 5, ACH Electrical Data, S=Single Fan Row, D=Dual Fan Row 208-230/3/60 460/3/60 575/3/60
Model No. of Rows
No. of Fans per
Row FLA MCA MOPD FLA MCA MOPD FLA MCA MOPD
UNIT kW
ACH 014A S 1 1 7.0 15.0 25 3.5 15.0 15 2.8 15.0 15 1.9
ACH 016A S 1 1 7.0 15.0 25 3.5 15.0 15 2.8 15.0 15 1.9
ACH 020A S 1 2 14.0 20.0 35 7.0 15.0 15 5.6 15.0 15 3.8
ACH 025A S 1 2 14.0 20.0 35 7.0 15.0 15 5.6 15.0 15 3.8
ACH 030A S 1 2 14.0 20.0 35 7.0 15.0 15 5.6 15.0 15 3.8
ACH 040A S 1 3 21.0 22.8 40 10.5 15.0 20 8.4 15.0 15 5.8
ACH 050A S 1 3 21.0 22.8 40 10.5 15.0 20 8.4 15.0 15 5.8
ACH 055A S 1 4 28.0 29.8 45 14.0 15.0 20 11.2 15.0 15 7.7
ACH 060A S 1 4 28.0 29.8 45 14.0 15.0 20 11.2 15.0 15 7.7
ACH 070A S 1 5 35.0 36.8 50 17.5 20.0 25 14.0 15.0 20 9.6
ACH 080A S 1 5 35.0 36.8 50 17.5 20.0 25 14.0 15.0 20 9.6
ACH 100A S 1 6 42.0 43.8 60 21.0 21.9 30 16.8 20.0 25 11.5
ACH 110A S 1 7 49.0 50.8 70 24.5 25.4 35 19.6 20.3 25 13.5
ACH 040A D 2 2 28.0 29.8 45 14.0 15.0 20 11.2 15.0 15 7.7
ACH 050A D 2 2 28.0 29.8 45 14.0 15.0 20 11.2 15.0 15 7.7
ACH 060A D 2 2 28.0 29.8 45 14.0 15.0 20 11.2 15.0 15 7.7
ACH 080A D 2 3 42.0 43.8 60 21.0 21.9 30 16.8 20.0 25 11.5
ACH 100A D 2 3 42.0 43.8 60 21.0 21.9 30 16.8 20.0 25 11.5
ACH 110A D 2 4 56.0 57.8 70 28.0 28.9 35 22.4 23.1 30 15.4
ACH 130A D 2 4 56.0 57.8 70 28.0 28.9 35 22.4 23.1 30 15.4
ACH 140A D 2 5 70.0 71.8 90 35.0 35.9 45 28.0 28.7 35 19.2
ACH 160A D 2 5 70.0 71.8 90 35.0 35.9 45 28.0 28.7 35 19.2
ACH 200A D 2 6 84.0 85.8 100 42.0 42.9 50 33.6 34.3 40 23.1
ACH 225A D 2 7 98.0 99.8 110 49.0 49.9 50 39.2 39.9 45 26.9
NOTE: MOPD = Motor Overload Protection Device.
12 IOMM A-C Cond
Table 6, ACL Electrical Data, S = Single Fan Row, D = Dual Fan Row 208-230/3/60 460/3/60 575/3/60
Model No. of Rows
No. of Fans per
Row FLA MCA MOPD FLA MCA MOPD FLA MCA MOPD UNIT kW
ACL 014A 1 1 6.6 15.0 25 3.3 15.0 15 2.6 15.0 15 1.4
ACL 016A 1 1 6.6 15.0 25 3.3 15.0 15 2.6 15.0 15 1.4
ACL 020A 1 2 13.2 15.0 30 6.6 15.0 15 5.2 15.0 15 2.7
ACL 025A 1 2 13.2 15.0 30 6.6 15.0 15 5.2 15.0 15 2.7
ACL 030A 1 2 13.2 15.0 30 6.6 15.0 15 5.2 15.0 15 2.7
ACL 040A 1 3 19.8 21.5 35 9.9 15.0 15 7.8 15.0 15 4.1
ACL 050A 1 3 19.8 21.5 35 9.9 15.0 15 7.8 15.0 15 4.1
ACL 055A 1 4 26.4 28.1 45 13.2 15.0 20 10.4 15.0 15 5.4
ACL 060A 1 4 26.4 28.1 45 13.2 15.0 20 10.4 15.0 15 5.4
ACL 070A 1 5 33.0 34.7 50 16.5 20.0 25 13.0 15.0 20 6.8
ACL 080A 1 5 33.0 34.7 50 16.5 20.0 25 13.0 15.0 20 6.8
ACL 100A 1 6 39.6 41.3 50 19.8 20.6 25 15.6 20.0 20 8.1
ACL 110A 1 7 46.2 47.9 60 23.1 23.9 30 18.2 20.0 25 9.5
ACL 040A 2 2 26.4 28.1 45 13.2 15.0 20 10.4 15.0 15 5.4
ACL 050A 2 2 26.4 28.1 45 13.2 15.0 20 10.4 15.0 15 5.4
ACL 060A 2 2 26.4 28.1 45 13.2 15.0 20 10.4 15.0 15 5.4
ACL 080A 2 3 39.6 41.3 50 19.8 20.6 25 15.6 20.0 20 8.1
ACL 100A 2 3 39.6 41.3 50 19.8 20.6 25 15.6 20.0 20 8.1
ACL 110A 2 4 52.8 54.5 70 26.4 27.2 35 20.8 21.5 25 10.8
ACL 130A 2 4 52.8 54.5 70 26.4 27.2 35 20.8 21.5 25 10.8
ACL 140A 2 5 66.0 67.7 80 33.0 33.8 40 26.0 26.7 30 13.5
ACL 160A 2 5 66.0 67.7 80 33.0 33.8 40 26.0 26.7 30 13.5
ACL 200A 2 6 79.2 80.9 90 39.6 40.4 45 31.2 31.9 35 16.2
ACL 225A 2 7 92.4 94.1 110 46.2 47.0 50 36.4 37.1 40 18.9
NOTE: MOPD = Motor Overload Protection Device.
Table 7, ACX Electrical Data, S = Single Fan Row, D = Dual Fan Row 460/3/60 208-230/3/60No. of
Fans per Row
No. of Fans
Model FLA MCA MOPD FLA MCA MOPD
UNIT kW
ACX 014A S 1 1 4.8 15.0 15 2.4 15.0 15 1.1ACX 016A S 1 1 4.8 15.0 15 2.4 15.0 15 1.1ACX 020A S 1 2 9.6 15.0 20 4.8 15.0 15 2.2ACX 025A S 1 2 9.6 15.0 20 4.8 15.0 15 2.2ACX 030A S 1 2 9.6 15.0 20 4.8 15.0 15 2.2ACX 040A S 1 3 14.4 20.0 25 7.2 15.0 15 3.4ACX 050A S 1 3 14.4 20.0 25 7.2 15.0 15 3.4ACX 055A S 1 4 19.2 20.4 30 9.6 15.0 15 4.5ACX 060A S 1 4 19.2 20.4 30 9.6 15.0 15 4.5ACX 070A S 1 5 24.0 25.2 35 12.0 15.0 15 5.6ACX 080A S 1 5 24.0 25.2 35 12.0 15.0 15 5.6ACX 100A S 1 6 28.8 30.0 40 14.4 20.0 20 6.7ACX 110A S 1 7 33.6 34.8 45 16.8 20.0 20 7.8ACX 040A D 2 2 19.2 20.4 30 9.6 15.0 15 4.5ACX 050A D 2 2 19.2 20.4 30 9.6 15.0 15 4.5ACX 060A D 2 2 19.2 20.4 30 9.6 15.0 15 4.5ACX 080A D 2 3 28.8 30.0 40 14.4 20.0 20 6.7ACX 100A D 2 3 28.8 30.0 40 14.4 20.0 20 6.7ACX 110A D 2 4 38.4 39.6 50 19.2 20.0 25 8.9ACX 130A D 2 4 38.4 39.6 50 19.2 20.0 25 8.9ACX 140A D 2 5 48.0 49.2 60 24.0 24.6 30 11.2ACX 160A D 2 5 48.0 49.2 60 24.0 24.6 30 11.2ACX 200A D 2 6 57.6 58.8 70 28.8 29.4 35 13.4ACX 225A D 2 7 67.2 68.4 80 33.6 34.2 40 15.6
NOTES: 1. MOPD = Motor Overload Protection Device. 2. Model ACX units are not available in 575 volts.
IOMM A-C Cond 13
Figure 3, Eight Fan, Two Row Wiring with Optional Pressure Switch and FanTrol™
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DC
ON
TRO
L
M3
M4
M5
M6
M7
L1L2
L3M
8L1
L2
L3
L1L2
L3
L1L2
L3
L1L2
L3
L1L2
L3
T1
T2
T3
T1
T2
T3
T1
T2
T3
T1
T2
T3
T1
T2
T3
T1
T2
T3L3
L2
L1
L3
L2
L1
L3
L2
L1
L3
L2
L1
L3
L2
L1
L3
L2
L1
C8
C7
C6
C5
C4
C3F3
F4F5
F6F7
F8
C8
C7
C6
C5
C4C3
C2
C1
FCP
1
FCP
2
FCP
3
FCP
4
FCP
5
FCP
6
FCP
7
FCP
8
GN
DTE
RM
INAL
BO
AR
D
T1T2
MC
QU
AY P
RE
SSU
RE
FA
N C
YC
LIN
GFA
NS/
CIR
CU
IT2 3 4
FCP
#1, #
219
0/14
0
190/
140
190/
140
FCP
#3, #
4FC
P #5
, #6
FCP
#7, #
8
230/
170
230/
170
220/
160
230/
170
220/
160
210/
150
ADJU
STA
BLE
RAN
GE
(M
INIM
UM
RA
NG
E 12
5 -2
50#)
(DIF
FER
ENTI
AL R
ANG
E 20
- 10
0#)
SEE
NO
TE 5
14 IOMM A-C Cond
Figure 4, Ten Fan, Two Row, Wiring with Optional Pressure Switch and Fantrol Control
FAN
MO
TOR
IDE
NTI
FIC
ATIO
N
ELEC
TRIC
BO
X
HEADEREND
NO
TE:
1. U
NIT
MU
ST
BE G
RO
UN
DE
D2.
TO
BE
FIE
LD F
USE
D, R
EFE
R T
O U
NIT
DAT
A P
LATE
FO
R V
OLT
AGE
3. A
LL M
OTO
RS
AR
E IN
HE
RE
NTL
Y
P
RO
TEC
TED
4. U
SE
60°
C W
IRE
5. W
IRE
D O
NLY
WIT
H C
ON
TRO
L C
IRC
UIT
TRA
NS
FOR
ME
R O
PTIO
N6.
US
E C
OPP
ER C
ON
DU
CTO
RS
ON
LY
LEG
END
:C
1-C
10 F
AN C
ON
TAC
TOR
M1-
M10
FA
N M
OTO
RFC
P F
AN
CY
CLE
PR
ESSU
RE
CO
NTR
OL
F1-F
10 F
US
ES (
RE
FER
TO
LA
BEL
AD
JAC
ENT
TO F
US
E H
OLD
ER
FO
R R
EP
LAC
EME
NT)
OP
TIO
NM
AIN
PO
WE
R C
IRC
UIT
3PH
/50/
60H
Z
DO
OR
DIS
CO
NN
EC
TS
WIT
CH
GN
D
L1L2
L3
TER
MIN
AL
BO
ARD
T1T2
T3
460V
OR
230V
INPU
T
F1
24V
L1L2
C1
TRANFORMER
F2 C2
GN
D
P66
GN
D
L1 M1
GN
D
L1 M1
P66
GN
D
ELE
CTR
ON
ICFA
NS
PEE
DC
ON
TRO
L
ELE
CTR
ON
ICFA
NS
PEE
DC
ON
TRO
L
VAR
IABL
E S
PE
EDC
ON
TRO
L M
OTO
R
M1
L2R
L1C
S
VAR
IAB
LE S
PEED
CO
NTR
OL
MO
TOR
L2R
L1C
S
M2
L2
T1
T2
L1
L2
T1
T2
L1
MC
QU
AY P
RES
SUR
E F
AN C
YCLI
NG
FAN
S/C
IRC
UIT
5.6
FCP#
1, #
219
0/14
0FC
P#3,
#4
210/
150
FCP#
5, #
622
0/16
0FC
P#7,
#8
230/
170
ADJU
STAB
LE R
ANG
E (
MIN
IMU
M R
ANG
E 12
5 - 2
50#)
(DIF
FER
EN
TIAL
RA
NG
E 2
0 - 1
00#)
C10C8 C9
C7
C6
C5
FCP
8
FCP
7
FCP
6
FCP
5
C4
C3
C2C1
FCP
1
FCP
2
FCP
3
FCP
4
GN
DTE
RM
INAL
BO
AR
D
115V
FAN
CO
NTR
OL
CIR
CU
IT1P
H/5
0/60
HZ
15 A
MP
S M
AX
OV
ERC
UR
RE
NT
PR
OTE
CTI
ON
T1T2
F10
C10
M10
M9
M8
F9 C9
F8 C8
TRA
NSF
OR
MER
F73A
-500
V
SEE
NO
TE 5
F3F4
F5F6
F7 C7
C6
C5
C4
C3
L1
L2
L3
T1
T2
T3
L1
L2
L3
T1
T2
T3
L1
L2
L3
T1
T2
T3
L1
L2
L3
T1
T2
T3
L1
L2
L3
T1
T2
T3
L1
L2
L3
T1
T2
T3
L1
L2
L3
T1
T2
T3
L1
L2
L3
T1
T2
T3
L1L2
L3M
7M
6M
5M
4M
3
L1L2
L3
L1L2
L3
L1L2
L3
L1L2
L3L1
L2
L3
L1L2
L3
L1L2
L3
OP
TIO
N
IOMM A-C Cond 15
Figure 5, Twelve Fan, Two Row, Wiring with Optional Pressure Switch and FanTrol
115V
FAN
CO
NTR
OL
CIR
CU
IT1P
H/5
0/60
HZ
15 A
MP
S M
AX
OV
ER
CU
RR
EN
T PR
OTE
CTI
ON
ELE
CTR
IC B
OX
FAN
MO
TOR
IDE
NTI
FIC
ATIO
N
HEADEREND
NO
TE:
1. U
NIT
MU
ST
BE
GR
OU
ND
ED
2. T
O B
E F
IELD
FU
SED
, RE
FER
TO
UN
IT D
ATA
PLA
TE F
OR
VO
LTA
GE
3. A
LL M
OTO
RS
AR
E IN
HE
RE
NTL
Y
P
RO
TEC
TED
4. U
SE
60°
C W
IRE
5. W
IRED
ON
LY W
ITH
CO
NTR
OL
CIR
CU
IT T
RAN
SFO
RM
ER O
PTI
ON
6. U
SE
CO
PP
ER
CO
ND
UC
TOR
S O
NLY
LEG
EN
D:
C1-
C12
FA
N C
ON
TAC
TOR
M1-
M12
FA
N M
OTO
RFC
P F
AN
CY
CLE
(R
EFE
R T
O L
AB
EL
AD
JAC
EN
T TO
FU
SE
HO
LDE
R
FO
R R
EP
LAC
EM
EN
T)
OP
TIO
N
TRA
NSF
OR
ME
RF7
3A-5
00V
SEE
NO
TE 5
DO
OR
DIS
CO
NN
EC
TS
WIT
CH
MA
IN P
OW
ER
CIR
CU
IT3P
H/5
0/60
HZ
GN
D
TER
MIN
AL
BO
AR
D
L1L2
L3
T1T2
T3
OP
TIO
N
F1
460V
OR
230V
INP
UT
F2
24V
L1L2
TRANSFORMER
C2
L1
L2
T1
T2
C1
L1
L2
T1
T2
GN
D
P66
L1 M1
GN
D
ELE
CTR
ON
ICFA
NS
PE
ED
CO
NTR
OL
P66
L1 M1
GN
D
ELE
CTR
ON
ICFA
NS
PE
ED
CO
NTR
OL
GN
D
M1
M2
L2 R
L1 C
S
VAR
IAB
LE S
PEE
DC
ON
TRO
L M
OTO
R
L2 R
L1 C
S
VAR
IAB
LE S
PEE
DC
ON
TRO
L M
OTO
R
MC
QU
AY P
RES
SU
RE
FAN
CYC
LIN
GFA
NS
/CIR
CU
IT5.
6FC
P#1,
#2
190/
140
FCP
#3, #
421
0/15
0FC
P#5
, #6
220/
160
FCP#
7, #
823
0/17
0A
DJU
STA
BLE
RA
NG
E (
MIN
IMU
M R
AN
GE
125
- 25
0#)
(DIF
FER
ENTI
AL
RA
NG
E 2
0 - 1
00#)
C12C10C11C9
C8C5
FCP
8
FCP
7
FCP
6
FCP
5
C6C7
FCP
1
FCP
2
FCP
3
FCP
4C
4
C3
C2
C1
GN
DTE
RM
INAL
BO
AR
DT1
T2
F12
C12
F11
C11
F10
C10
F9 C9
F8 C8
F7 C7
F6 C6
F5 C5
F4 C4
F3 C3
M3
M4
M5
M6
M7
M8
M9
M10
M11
M12
L1L2
L3
L1L2
L3
L1L2
L3
L1L2
L3
L1L2
L3
L1L2
L3
L1L2
L3
L1L2
L3
L1L2
L3
L1L2
L3
L1
L2
T1
T2
L3 T3
L1
L2
T1
T2
L3 T3
L1
L2
T1
T2
L3 T3
L1
L2
T1
T2
L3 T3
L1
L2
T1
T2
L3 T3
L1
L2
T1
T2
L3 T3
L1
L2
T1
T2
L3 T3
L1
L2
T1
T2
L3 T3
L1
L2
T1
T2
L3 T3
L1
L2
T1
T2
L3 T3
16 IOMM A-C Cond
Figure 6, Twelve Fan, ACH/ACL/ACX, Wiring with Contactors for Field Installed Control
F AN
MO
TOR
IND
ENTI
FIC
ATIO
N
HEADEREND
ELE
CT R
IC B
OX
NO
TE:
1. U
NIT
MU
ST
BE
GR
OU
ND
ED
2. T
O B
E F
IELD
FU
SED
, REF
ER
TO
UN
IT D
ATA
PLA
TE F
OR
VO
LTA
GE
3. A
LL M
OTO
RS
AR
E IN
HE
RE
NTL
Y
P
RO
TEC
TED
4. U
SE
60°
C W
IRE
5. 1
15 V
OLT
CO
NTR
OL
CIR
CU
IT6.
US
E C
OP
PE
R C
ON
DU
CTO
RS
ON
LY
LEG
EN
D:
C1-
C12
FA
N C
ON
TAC
TOR
M1-
M1 2
FA
N M
OTO
RFC
P F
AN
CY
CLE
PR
ES
SUR
E C
ON
TRO
LF1
-F12
FU
SE
S (R
EFE
R T
O L
AB
EL
A
DJA
CE
NT
TO F
USE
HO
LDE
R
FO
R R
EP
LAC
EM
EN
T)
OP
TIO
NTR
AN
SFO
RM
ER
F73A
-500
V
MAI
N P
OW
ER
CIR
CU
IT3P
H/5
0/60
HZ
DO
OR
DIS
CO
NN
ECT
SWIT
CH
GN
D
L1L2
L3
TER
MIN
AL
BO
AR
DT1
T2T3
460V
OR
250V
INPU
T
F124
V
L1L2
OP
TIO
NC
1
GN
D
TRANSFORMER
GN
D
L2
L1 T1
T2
P66
GN
D
L1 M1
M1
ELE
CTR
ICFA
NSP
EED
CO
NTR
OL
VAR
IABL
E S
PEE
DC
ON
TRO
L M
OTO
R
ELE
CTR
ICFA
NS
PEED
CO
NTR
OL
P66
GN
D
L1 M1
L2 R
L1 C
S
VAR
IABL
E SP
EE
DC
ON
TRO
L M
OTO
R
M2
S
L1 C
L2 R
TER
MI N
AL
BO
AR
DS
FOR
FIE
LD C
ON
TRO
LO
F FA
N C
ON
TAC
TOR
S
TER
MIN
AL
BOAR
D 6
T2 T1C
11C8C7
C5
C3
C1
C12
C10C9
C6
C4
C2
TER
MIN
ALB
OA
RD
5
TER
MIN
ALBO
ARD
4TE
RM
INAL
BOAR
D 1
0
TER
MIN
ALBO
ARD
11
TER
MIN
ALBO
ARD
12
TER
MIN
ALBO
ARD
9TE
RM
INA
LB
OA
RD
3
TER
MIN
AL
BO
AR
D 2
TER
MIN
AL
BO
AR
D 8
TER
MIN
AL
BOAR
D 7
TER
MIN
ALBO
ARD
1
T2 T1T2 T1
T2 T1T2 T1T2 T1T2 T1T2 T1T2 T1
T2 T1 T2 T1 T2 T1
FAN
CO
NTR
OL
CIR
CU
IT1P
H/5
0/60
HZ
1 5 A
MP
S M
AX
OV
ER
CU
RR
EN
T P
RO
TEC
TIO
N
M3
M4
M5
M6
M7
M8
M9
M10
M11
M12
L1L2
L3
L1L2
L3
L1L2
L3
L1L2
L3
L1L2
L3
L1L2
L3
L 1L2
L3
L1L2
L3
L1L2
L3
L1L2
L3
C3
C4
C5
C6
C7
C8
C9
C10
C11
C12F1
2
F11
F10
F9
F8
F7
F6
F5
F4
F3
L1
L2
L3
T1
T2
T3
L1
L2
L3
T1
T2
T3
L1
L2
L3
T1
T2
T3
L1
L2
L3
T1
T2
T3
L1
L2
L3
T1
T2
T3
L1
L2
L3
T1
T2
T3
L1
L2
L3
T1
T2
T3
L1
L2
L3
T1
T2
T3
L1
L2
L3
T1
T2
T3
L1
L2
L3
T1
T2
T3
IOMM A-C Cond 17
Operation
Start-Up Check for proper fan rotation. Air is drawn through the coil on all units. Be sure the fans turn freely. Rotation of the motors and blades should be in a "clock-wise" direction looking at the unit from the blade side. On three-phase units, it may be necessary to reverse two of the three power leads to the unit.
Discharge Gas Pulsation Gas pulsations in a refrigeration system are most commonly associated with the compressor and connecting discharge piping. Variations in the system piping configuration, line sizing, operating pressures and compressor and component mounting all contribute to the presence and magnitude of these pulsations. The vibration and movement of components caused by the pulsations may result in line breakage or damage to the condenser. Install a discharge muffler in the refrigeration piping to eliminate discharge pulsations and the potential for related condenser damage. Follow the recommendations of the compressor or muffler manufacturer when selecting these components.
Discharge Pressure Control Proper application of controls is important to a successful installation. McQuay air-cooled condensers have several options to meet the needs. The capacity of an air-cooled condenser varies with the difference between the entering air dry bulb temperature and the condensing temperature of the refrigerant. Since air temperature varies from summer to winter, the condensing temperature must be kept high enough to ensure proper operation of the refrigerant expansion valve during low ambient air temperature operation, and also allow enough capacity so excessively high condensing temperatures do not occur during high ambient conditions. The low limit of the head pressure is dependent upon the required pressure drop across the thermostatic expansion valve. For normal air conditioning applications, maintain head pressure above a condensing temperature corresponding to 90°F. This corresponds to a normal lower limit of about 60°F ambient air. When operation is required below 60°F ambient air temperature, additional head pressure control will be required. A decrease in ambient air temperature results in a capacity increase in the air-cooled condenser. This capacity increase is directly proportional to the temperature difference between the condensing temperature and the temperature of the ambient air entering the condenser. Air-cooled condensers are often required to operate over a wide range of ambient air temperatures and variable loading conditions so provisions must be made to maintain the overall system balance. Low head pressures cause poor expansion valve operation and poor system operation.
The cycling of condenser fans provides an automatic means of maintaining head pressure control, within reasonable limits, at lower ambient air temperatures. A fan cycling control system allows fans to cycle in sequence by sensing condensing pressures. Short cycling is normally caused by too close a differential in the control settings or setpoints. If field supplied flooding valves are used with fan cycling, set valves to follow the fan cycling. Set pressure switches to at least 35 PSIG differential setting.
Any fan cycle that is less than three minutes is considered short cycling, and could be detrimental to the system. Adjust controls accordingly.
Use optional SpeedTrol™ variable speed fan control for operation below 35°F ambient air temperature
18 IOMM A-C Cond
Fan/Circuit Configuration Fan Rows: All models have either one or dual rows of fans with up to seven fans per row, a maximum total of 14 fans for a dual row unit. The number of fan rows and fans is shown in various tables where appropriate.
Refrigerant Circuits: Dual row condensers have two refrigerant circuits, one for each row of fans and match up with McQuay WGZ and WGS chillers, which have two circuits. The two refrigerant circuits can be optionally equipped with a factory manifold to make one refrigerant circuit.
Single row condensers have a single refrigerant circuit and must be used in pairs on McQuay chillers, each condenser matched to one of the chiller circuits. A pair of single row units is usually only used in the rare case when space requirements dictate two long narrow condensers end to end or when they are in separate locations.
The single row configuration allows more ambient air to flow through the coils than does a unit with a dual row, side-by-side fans and so they often have a little more capacity than a two row unit with the same number of fans. For a given capacity, two single row condensers will cost more than a single dual row unit.
Dual fan, two circuit condensers can be manifolded together to form a single refrigeration circuit.
Control options: One of four control options will have been supplied on any unit. Other special options can be offered to meet individual requirements.
1. Standard Control (Code NN) The standard unit is provided with a contactor for each fan motor. A customer-supplied, and field-installed, control signal from another source is required to energize each contactor based on the condenser pressure. Field wiring between the compressorized product and remote condenser is required. Refer to local codes for this wiring. The contactor control voltage is 115 volts and a transformer is not provided but is an available option. Typical control logic is to start additional fans as condensing pressure increases. Although the parameters of the companion refrigeration system dictates, it is good practice to only use this option only for operation above ambient air temperatures of 35°F. Standard Control Using Chiller MicroTech II® Control Staging The Standard Control (Code NN) or Standard Control with SpeedTrol (Code ST) added can utilize the standard pressure sensing capability of a McQuay chiller’s MicroTech II controller(s) to stage the fans. The WGZ chiller has a single microprocessor with eight fan control digital outputs, four for each refrigerant circuit. The WGS chiller has a separate controller for each of the two circuits with six fan stages, for a total of twelve for the unit.
Field wiring is required between the chiller MicroTech II controller and the fan contactors located in the condenser. The number of connections will depend on the condenser size and arrangement as show in Table 12 or Table 13.
This option uses the standard condenser control included with the condenser and the standard MicroTech II control included with the chiller. Field-supplied interconnecting wiring is the only cost. It does not provide variable speed for operation below 35°F. Use control option #2 to add variable speed for operation from 0°F to 35°F.
IOMM A-C Cond 19
2. Standard Control with SpeedTrol (Code ST) This option is identical to the Standard Control (Code = NN) except the “first on, last off” fan will have a variable speed drive. As the ambient air temperature drops below 35°F, the fan speed will slow down, reducing condenser air flow, to maintain the minimum allowable condensing pressure for the companion unit. A control transformer is provided to power the variable speed drive. Important: This option by itself does not include a method of starting or cycling the balance of fans on the condenser. Some means to do so must be supplied, mounted and wired in the field. The MicroTech II controller on McQuay WGZ or WGS chillers can provide this staging function or some other multi-step controller. Setting: SpeedTrol is performed by a Johnson Controls P66 Electronic Fan Speed Control driving a single-phase fan motor. The control senses discharge pressure and varies the voltage to the motor and hence its speed. Operation is in accordance with the following table.
Table 8, P66 Speed Control Operation Pressure Input Motor Voltage (VAC, True RMS)
Pressure is between 0 psig and the low end of the operating range. 0 to 5 volts, motor off
Start voltage (10% to 40% of line volts, model specific) Pressure is at the low end of the operating range.
Motor voltage (and fan speed) varies directly with pressure from the start voltage to 90% of line volts. Pressure is in the operating range.
A further pressure increase of 20 to 30 psi will increase motor voltage to 97% of the applied volts. Pressure is above the operating range.
The setting of the P66 control must be coordinated with the settings of the fan staging controls, so that the fan is the first fan to start and the last to shut off. To adjust the operating range, locate the adjustment screw on the control’s transducer. The screw can be accessed through the opening in the upper left-hand corner of the control’s base. Turn the screw clockwise to increase, or counterclockwise to decrease, the operating range. One turn equals approximately 35 psig of change.
A P66AAB-9 control is used for R-22. It has an operating (throttling) range of 170 to 230 psig. This 60 psi throttling range is not adjustable. The adjustment moves the entire range up or down. For example, one screw turn clockwise will change the setting from 170/230 psig to 205/265 psig.
20 IOMM A-C Cond
Figure 7, SpeedTrol Operating Range
No fan operationin this
pressure range.Throttling
Range
Operating Range(i.e., 190/250 psig)
Operating RangePlus 20 or 30 psi*
350 psigPressure Input
97%
90%
Mot
or V
olta
ge
0psig
*20 psi for 30 psi Effective Throttling Range (ETR)30 psi for 60 psi Effective Throttling Range (ETR)
The setting of the speed control must be coordinated with pressures switch settings (or MicroTech II staging) so that the fan starts (at minimum speed) when the pressure switch closes, starting the fan. As the discharge pressure increases, the fan speed will increase. Additional fans may stage on and the control should float the # 1 fan speed up and down as the fans stage on, avoiding sudden changes in discharge pressure that can upset unit operation, especially expansion valve control. With the first fan on, set the fan control to start the motor at the same pressure.
Table 9, Troubleshooting Chart Problem Possible Causes Possible Solution
Input pressure is below operating range. No problem, normal operation. No 24 volt control voltage. Check for 24 VAC at control.
Alignment. Schrader valve not depressed sufficiently. No input pressure to control.
Disconnect power. Place a jumper from L to M, and reconnect power. If fan does not run, motor is bad and should be replaced.
Bad fan motor
No fan operation
See Pressure Transducer Troubleshooting following. Pressure transducer problem
Fan stops when pressure reaches the high end of the operating range.
Control is not wired correctly See wiring diagram
Control is not wired correctly See wiring diagram No fan modulation Fan starts at full speed See Pressure Transducer
Troubleshooting following Pressure transducer problem Erratic fan operation Fan motor is cycling on thermal overload Dirty or blocked condenser coil Clean condenser coil
Pressure Transducer Troubleshooting 1. Disconnect 6-pin connector from the right side of control. 2. Place a jumper wire between third pin from the top and the bottom pin on the control,
not the cable. a. If the fan goes to full speed, check for input pressure b. If there is adequate pressure, the transducer is bad and the control must be replaced.
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3. Optional Pressure Switch Control with Control Transformer (Ordering Code = MH) This option provides direct control of discharge pressure through a series of factory-mounted and wired pressure switches (designated as FCP-Fan Cycle Pressure Control-on the wiring diagrams). As the condenser pressure increases, more pressure switches close and start additional condenser fans. Field wiring between the compressorized product and the remote condenser is not required. A control power transformer is included for 115 volt power for the control voltage. The parameters of the refrigerant system dictates, but, it is good practice to only use this option only for operation above ambient air temperatures of 35°F. Setting: The fan pressure switches (FCP) are set per the following table. For example, a setting of 190-140 means that the switch closes at 190 psig starting the fan and opens at 140 psig, shutting it off
Table 10, Electronic Fan Cycling Thermostat Settings S350 Temperature Stage Number of Fans Modules Offset Settings Design
T.D. A350 Setpoint Double Ro ws Single Row 2 3 4 5
30 60
2 4 25 65 20 70 15 75 10 80 30 60 20
3 6 25 65 10 20 70 10 15 75 10 10 80 15 30 60 10 30
4 8 25 65 10 25 20 70 5 20 15 75 5 15 10 80 5 10
60 5 15 30 30 65 5 15 30 5 10 25 70 5 10 30 20 75 5 10 20 15 10 80 5 10 15
30 55 5 15 25 30 25 65 5 10 20 30
6 / 7 12 / 14 20 70 5 10 20 30 15 75 5 10 15 25 10 80 5 10 15 20
NOTES 1. Johnson Controls Style S350 operation. 2. 5° differential set on all modules. All modules set in the “heating” mode.
Table 11, Fan Pressure Switch Settings Control Settings Pressure Switch
Cut-In Settings Number of Fans Design T.D Refrigerant
Single Row
Double Rows PC1 PC2 PC3 PC4 PC5
2 4 20 R134a 147 R22 215
3 6 20 R134a 147 155 245 R22 215
4 8 20 R134a 147 155 231
160 247 R22 215
5 10 20 R134a 147 153 225
156 236
160 247 R22 215
R134a 147 150 223
153 230
157 239
160 247 6 / 7 12 / 14 20 R22 215
NOTES 1. Based on 20º T.D. 2. For R134A set cutout 25 PSIG below cut-in. 3. Fan on header end to remain on whenever compressor is operating.
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4. Optional Pressure Switch Control with Control Transformer & SpeedTrol (Code=VM) This option is identical to the pressure switch control system described above except with the addition of variable speed control to the “first on, last off” fan for each circuit. The fan pressure switches should be set per Table 11. The P66 fan speed controller is set as explained in Section 2, above.
Standard Control (Code NN) or SpeedTrol (Code ST) Using Unit MicroTech II Control Staging The Standard Control (Code NN) or Standard Control with SpeedTrol (Code ST) can utilize the pressure sensing capability of a McQuay chiller’s MicroTech II controller(s) to stage the fans. The WGZ chiller has a single microprocessor with eight fan control digital outputs, four for each refrigerant circuit. The WGS chiller has a separate controller for each of the two circuits with six fan stages, for a total of twelve for the unit.
Field wiring is required between the chiller controller(s) and the fan contactors located in the condenser. The number of connections will depend on the condenser size and arrangement as show in the table below.
Table 12, WGZ Fan Staging and Field Wiring Circuits Fan Stage
1 2 3 4 5 6 7 8 Fans
Circuit #1 Circuit#2 1 3 2 4 - - 4 1 3 5 2 4 6 6 1 3 5 7 2 4 6 8 8 1 3 5 7, 9 2 4 6 8, 10 10 1 3 5, 7 9, 11 2 4 6, 8 10, 12 12
Table 13, WGS Fan Staging and Field Wiring Circuits Fan Stage
Fans Circuit #1 Circuit#2
1 2 - - - - 1 2 - - - - 4 1 2 3 - - - 1 2 3 - - - 6 1 2 3 4 - - 1 2 3 4 - - 8 1 2 3 4 5 - 1 2 3 4 5 - 10 1 2 3 4 5 6 1 2 3 4 5 6 12
Fan Locations 12 10 8 6 4 2
Circuit #2
11 9 7 5 3 1 Electric Panel
Circuit #1
6 5 4 3 2 1 Electric Panel Circuit #1
Flooding Head Pressure Controls Another means of head pressure control is to change the condenser capacity by filling the inside of the condenser with liquid refrigerant. Flooding controls are ideal for condensers operating in low ambient conditions (beyond the limits of fan cycling controls) or under partial load conditions. These controls require additional refrigerant charge (and a receiver) to flood the condenser. This additional refrigerant charge can often be reduced by incorporating the flooded control with one of the fan cycle controls previously described.
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Several styles of flooding valves or combinations of valves are available. Contact the valve manufacturer for specific recommendations.
Refrigerant Charge
The refrigerant charge for summer operation can be found in Table 14. This table also contains the additional charge required by flooding style controls when fan control is not also used. Table 16 contains the recommended flooding charge required when combining fan cycling with flooding valves. The addition of fan cycling to flooded control greatly reduces the required refrigerant charge.
Table 14, Refrigerant Charge. (lbs). R-22 for Flooded Condenser Without Fan Cycling (Times 0.99 for R-134a)
Additional Refrigerant R-22 Charge Required for Flooded Condenser Operation Lbs. For 20°F TD Minimum Ambient at
Condenser
Refrigerant R-22 Charge for Summer Operation,
Lbs.
Model ACH ACL ACX +60 +40 +20 +0 -20
8 7 10 11 11 11 014A-S 10 10 13 15 15 16 016A-S 10 10 13 14 15 15 020A-S 15 15 19 21 22 23 025A-S 29 30 39 43 45 47 030A-S 22 22 29 32 34 35 040A-S 30 29 38 42 44 46 050A-S 70 66 87 96 100 105 060A-S 64 62 83 92 95 99 070A-S 86 83 110 122 127 132 080A-S 102 100 132 147 153 159 100A-S 118 117 155 172 179 186 110A-S 19 20 27 29 31 32 040A-D 29 30 39 44 46 47 050A-D 40 39 51 57 59 62 060A-D 44 44 58 64 67 70 080A-D 58 59 78 86 90 94 100A-D 104 99 131 146 152 158 110A-D 140 131 174 193 201 209 130A-D 125 126 168 186 194 201 140A-D 172 165 219 243 253 263 160A-D 201 201 267 296 308 320 200A-D 236 233 310 343 357 372 225A-D
NOTE: See for factors for Temperature Differences other than 20 degrees.
24 IOMM A-C Cond
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Table 15, Flooded Charge Temperature Difference Factor Design T.D. Ambient, °F
30 25 20 15 10 60 -- 0.38 1.0 1.74 2.46 40 0.59 0.80 1.0 1.19 1.40 20 0.76 0.88 1.0 1.13 1.25 0 0.84 0.91 1.0 1.07 1.16
-20 0.88 0.93 1.O 1.06 1.13
Table 16, Refrigerant Charge for Flooded Condenser With Fan Cycling (lbs.) R-22 (Times 0.99 for R-134a)
25° TD 20° TD 15° TD 10° TD Ambient temperature (°F)
Model ACH ACL ACX 40 20 0 -20 40 20 0 -20 40 20 0 -20 40 20 0 -20
014A-S 7 8 9 9 8 9 10 10 9 10 11 11 13 12 12 12 016A-S 9 12 13 14 11 13 14 15 13 14 15 16 17 18 17 18 020A-S 1 6 8 10 4 8 10 11 7 10 12 13 10 13 14 14 025A-S 2 9 12 15 7 12 15 17 12 16 18 19 17 19 21 22 030A-S 4 17 24 29 14 24 30 34 24 31 36 39 33 38 41 43 040A-S 0 3 10 15 0 10 16 20 0 17 22 25 0 24 27 29 050A-S 0 4 13 20 0 12 20 26 0 21 27 32 0 29 34 38 055A-S 0 0 8 22 0 6 23 35 0 22 38 48 0 37 52 61 060A-S 0 0 11 29 0 8 31 46 0 29 51 63 0 49 71 80 070A-S 0 0 0 15 0 0 17 33 0 0 39 52 0 0 60 70 080A-S 0 0 0 19 0 0 22 44 0 0 50 69 0 0 78 93 100A-S 0 0 0 6 0 0 8 37 0 0 37 69 0 0 66 100 110A-S 0 0 0 0 0 0 0 29 0 0 0 69 0 0 0 108 040A-D 3 12 17 20 9 17 21 23 15 22 25 26 21 27 29 29 050A-D 4 17 24 29 13 24 30 34 22 31 36 39 31 38 41 43 060A-D 5 22 32 38 17 31 39 44 29 40 46 50 41 49 53 56 080A-D 0 5 20 31 0 18 31 40 0 31 42 49 0 44 53 59 100A-D 0 7 27 42 0 25 42 54 0 43 57 66 0 61 71 79 110A-D 0 0 17 44 0 12 47 69 0 43 77 95 0 74 107 119 130A-D 0 0 22 57 0 16 62 91 0 57 102 125 0 99 141 157 140A-D 0 0 0 30 0 0 34 67 0 0 77 105 0 0 120 141 160A-D 0 0 0 39 0 0 44 88 0 0 100 137 0 0 156 186 200A-D 0 0 0 11 0 0 16 74 0 0 74 137 0 0 132 200 225A-D 0 0 0 0 0 0 0 57 0 0 0 135 0 0 0 213
NOTE: See Table 14 for summer charge.
Maintenance
Air-cooled condensing units require a minimum of maintenance. The unit coil will require a periodic cleaning. Clean the unit using a brush, vacuum cleaner, pressurized air stream or a commercially available coil cleaning foam. All of the condenser fan motors have sealed ball bearings and do not need maintenance. If bearings fail, then replace bearings.
Cleaning Instructions ! CAUTION
Cautions indicate potentially hazardous situations, which can result in personal injury or equipment damage if not avoided.
Never clean this unit with an acid-based cleaner. Off-spray can be dangerous to health and the acids are corrosive to aluminum
components.
Clean the finned surface at least every six months; more frequent cleaning may be required if extreme conditions cause clogging or fouling of air passages through the finned surface.
Use Calgon Corporation's CalClean 41352 (or equal). Apply CalClean liberally to entering air and leaving air surfaces of the finned area according to label directions and rinse thoroughly to remove all cleaners.
26 IOMM A-C Cond
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