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Series 3800 Maintenance Manual Technical Manual 694T Farris Engineering Division of Curtiss-Wright Flow Control Corporation

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  • Series3800MaintenanceManual

    Technical Manual 694T

    Farris EngineeringDivision of Curtiss-Wright Flow Control Corporation


    I. INTRODUCTION ........................................................ 2

    II. SAFETY TIPS............................................................ 2

    III. OPERATIONAL PRINCIPLES .................................. 3

    IV. PILOT CONTROLS .................................................. 4(i) Disassembly .......................................................... 5(ii) Cleaning and Repairing ........................................ 5(iii) Assembly .............................................................. 6(iv) Setting and Testing............................................... 8

    V. MAIN VALVE ............................................................ 10(i) Disassembly ........................................................ 11(ii) Cleaning and Repairing ...................................... 11(iii) Assembly ............................................................ 11

    VI. FINAL ASSEMBLY ................................................. 12

    I. Introduction

    This Maintenance Manual is intended to present all theessential information you will need in order to keep yourFarris valves in perfect operating condition. Generally,maintenance becomes necessary as a result of dirt orscale in the lines, exposure to service conditions,incorrect servicing, improper testing procedure, orimproper installation.This manual covers Series 3800 pilot-operated safetyrelief valves, which consist of two basic components: apilot control (PCF 3) and the main valve. The pilot controlis a spring-loaded valve which senses the pressure andcontrols the opening and closing of the main valve.Once the pilot-operated safety relief valve is isolatedfrom the system pressure, relieve the pressure from theinlet valve. Disconnect the pilot control from the mainvalve. Take particular note of the tubing connectionorientation.

    Follow Section IV to perform maintenance on the pilotcontrol. Follow Section V to perform maintenance on themain valve.

    If a valve repair requires replacement of parts, onlyFarris components should be used. Use of parts fromother than the original manufacturer will lead to poten-tially dangerous operating conditions. This valve isASME Code certified. Unauthorized tampering andrepair is in violation of the Code and will void certifica-tion that may apply to an ASME Code certified system.If faced with repairs exceeding the scope of this manual,you should contact the Farris Factory.

    II. Safety Tips

    Make sure that the safety relief valve is isolated fromthe pressure source before it is removed.

    Stand clear and wear protective clothing when remov-ing safety relief valve to prevent exposure to any typesof deposits or corrosive debris which may have beentrapped inside the valve.

    Do not stand near the discharge side of a safety reliefvalve when testing the valve.

    Always install a safety valve vertically as the internalparts are designed to operate in that position.

    Avoid hammer blows to the valve.

    Eliminate stress on the valve body whenever possible.

    Be careful when checking a safety valve for visibleleakage.



    10195 Brecksville Road, Brecksville, Ohio 44141 Telephone (440) 838-7690 FAX (440) 838-7699 www.cwfc.com

    Farris EngineeringDivision of Curtiss-Wright Flow Control Corporation



  • 3III. Operational Principles

    (Refer to Figures 3.3 and 3.4)Pressure in the protected vessel is sensed through apressure tap (remotely connected or on the main valvebody). The pressure tap is piped to the pilot controlsensing line port. The vessel pressure is transmitted tothe dome from the pilot control dome port.When vessel pressure is below pilot control set pres-sure, the relief seat of the pilot control is closed. Inletpressure of the main valve is equal to the dome pres-sure. The difference in the main valve nozzle seat area(smaller) and the dome area (larger) guarantees themain valve to be closed.When the vessel pressure reaches set pressure, thepilot control relief seat opens instantaneously with theclosing of the lower seat. The pilot control relieves thedome pressure to the atmosphere. The force of the

    pressure in the inlet of the main valve causes the pistonto lift from its closed position to relieve excess vesselpressure. The relationship between the downward forceon the main valve piston and vessel pressure is illus-trated in Figure 3.1.When vessel pressure reaches re-seat pressure (typi-cally 95% of set pressure), the spring force overcomesthe pressure force on the lower seat of the pilot control.The relief seat closes instantaneously with the openingof the lower seat. Pressure re-enters the dome anddevelops the force to move the piston down and closethe main valve. In Figure 3.2, the lift of the main valvepiston is plotted against vessel pressure.

    Fig. 3.3

    Fig. 3.4





    Main Valve





    n Va



    on L

    ift (%


    Pressure Set

    Pressure Set



    d Fo





    e Pi


    Fig. 3.1

    Fig. 3.2



    1 Body2 Bonnet3 Cap4 Spring Adjusting Screw5 Upper Spring Button6 Spring7 Lower Spring Button8 Disc9 Jam Nut10 Guide11 Upper Seat Seal12 Upper Seat13 Static Seal, Body14 Blow Down Relay15 Lower Seat16 Retainer, Lower Seat Seal17 Lower Seat Seal18 Static Seal, Adjuster19 Blow Down Adjuster20 Filter Static Seal21 Filter22 Filter Housing23 Lower Disc24 Adjuster Cap Seal25 Blow Down Adjuster Cap26 Thread Seal, O-Ring27 Blow Down Adjuster Lock Nut28 Bug Vent Housing29 Wire Seal30 Name Plate (Fig. 4.1a)

    IV. Pilot Control




















    Fig. 4.1aSample PCF3 Nameplate

    Fig. 4.1PCF3 Pilot Control



    100 PSIG




  • 5(i) DisassemblyLike any other safety relief device, the PCF3 pilot controlrequires maintenance on a regular basis. Scheduling ofmaintenance is the responsibility of the end-user.The PCF3 pilot control shall be taken off-line before anymaintenance and service work can be performed.Arrangements for an alternate safety relief device shallbe made, if system protection is to remain in effect. Onlyauthorized repair facility with qualified personnel shall doany maintenance/repair.It is necessary to have the right tools (Table 4.1) and areplacement elastomer kit.

    Table 4.1

    ITEM TOOL DESCRIPTION SIZES1 Soft Jaw Bench Vise2 Adjustable Wrenches3 Set of Open End 1/4, 7/16, 9/16,

    Wrenches 5/8, 3/4, 1-1/8,1-1/2, & 2 Inch Span

    4 O-Ring Pick5 Wire Cutters

    Once the pilot control is out of service:1. Place the pilot control on a clean and well-lit work-

    bench.2. Make a note of the physical condition of the valve

    before disassembly.3. Cut and discard lead seals.4. Remove the strainer assembly, the fitting for the

    piston (dome) line, and the exhaust port attachment.5. Clamp the body of the valve on a bench vise.

    Remove the cap by unscrewing it from the bonnet.6. Relieve the spring compression by loosening the

    spring adjustment screw. Take note of the number ofturns from the locked position to the point wherespring resistance is not felt. This will aid in settingthe valve to its original set pressure.

    7. Remove the bonnet from the body to expose theinternals of the upper sub-assembly. CAREFULLYpull each part and arrange neatly on top of theworkbench.

    8. Loosen the blow down adjuster. Take note of thenumber of turns from the locked position to thelowest position. This will be helpful when setting thevalve to its original setting.

    9. Remove the lower sub-assembly by unscrewing thebushing from the body.

    10. Unscrew the seat insert from the adjuster to accessthe lower disc assembly.

    (ii) Cleaning and RepairingClean all parts with solvent and blow dry with air, beingparticularly careful on seating surfaces.Inspect all parts and seating surfaces for excessive wearand corrosion. Discard and replace as necessary. NOREMACHINING IS ALLOWED. Replace all seals.Identify each new elastomer piece from the kit bymatching it with Figure 4.2. Be sure to replace withproper compound for the particular service. If in doubt,contact the Farris Factory giving the serial number onthe nameplate.

    Fig. 4.2Seals for PCF3 Pilot Control

    (Full Scale)






  • 6(iii ) AssemblyThe upper and adjuster sub-assemblies have beenidentified in Figure 4.3 to help in distinguishing thevertical position of the PCF3. Orientation of all the partsin each sub-assembly is likewise referred to in theirvertical position.Lubricate all threaded and mating surfaces with BostikNever Seez (or equivalent).

    a. Upper Sub-Assembly1. Orient body with its length vertical, and the wider

    opening facing upward.2. Place a static seal into the counter-bore of the body,

    via the upper opening.3. Place the upper seat over the static seal, making

    sure the side with the bigger outside diameterprotrusion faces downward.

    4. Orient the guide with its flange upward. Insert theupper seat seal into the recess on the lower side ofthe guide.

    5. Lower the guide onto the upper seat inside the body,making sure that the upper seat seal does not fallout and is in good contact with the upper seat andthe guide. Also make sure that the two holes on theguides side face the outlet (uppermost side-hole) ofthe body.

    6. Slide disc into the guide, taking care not to damagethe seats, and making sure that the upper disc restsfully on the upper seat seal. The correct orientationof the disc is with its rounded end facing upwards.

    7. Place the two (2) spring buttons over the two endsof the spring. Hold the buttons over the ends of thespring with thumb and forefinger.

    8. Match the lower spring button over the rounded topof the disc making sure that rounded top of the discfits into the recess in the lower spring button.

    9. Lower the bonnet over the spring buttons sub-assembly and screw tightly into the body.

    10. Screw the spring adjusting screw into the jam nutuntil the jam nut is about two thirds (2/3) up thespring adjusting screw.

    11. Screw the spring adjusting screw jam nut sub-assembly into the top of the bonnet. Stop as soon asresistance from the upper spring button is felt.

    b. Adjuster Sub-Assembly1. Position the lower seat seal on the retainer making

    sure it fits evenly and symmetrically.2. Lower the retainer into the lower disc with the lower

    seat seal fitting snugly between the retainer and thelower seat.

    3. Lower the lower seat retainer sub-assembly intothe adjuster with the lower disc entering the adjusterfirst.

    4. Screw the seat insert into the adjuster and tighten.5. Place the second static seal in the groove on the

    side of the adjuster, making sure it fits evenly.6. Place the bushing seal on the bushing beyond the

    threads and against the flat back of the bushingshex head.

    7. Screw the bushing onto the adjuster with the hexhead of the bushing facing downward.

    8. Position a thread seal on the threads of the adjusterand against the hex head of the bushing.

    9. Screw the lock nut onto the adjuster and tighten.10. Place the spacer rod into the hole of the seat insert

    until it rests on the top of the retainer.11. Insert the adjuster sub-assembly into the body

    through its lower end, making sure the spacer rodpasses through the hole of the upper seat.

    c. Strainer1. Position the strainer into the inlet (lowest) port of the

    body, flange first.2. Place the second thread seal into the inlet port,

    bottoming on the strainer flange.3. Screw the strainer housing into the inlet port and


    d. Connections1. Connect the sensing line into the strainer housing in

    the sensing line port of the body.2. Use the dome line port in the middle of the body to

    connect to the dome of the main valve.3. Leave the exhaust port open to the atmosphere for

    exhaust, or connect it to an exhaust plenum.The PCF3 pilot control is ready to be set and tested.


  • 7Fig. 4.3PCF3 Exploded View


    Jam Nut

    Upper Spring Button

    Lower Spring Button


    Upper SeatStatic Seal


    Spacer Rod

    Seat Insert

    Lower Seat Seal

    Static Seal

    Bushing Seal

    Thread Seal

    Spring Adj. Screw




    Upper Seat Seal


    StrainerThread Seal

    Strainer Housing


    Lower Disc



    Lock Nut


  • 8(iv) Setting and TestingTesting of the PCF3 will be performed only after correctassembly has been accomplished. Read the entire testprocedure. Test should be conducted only by qualifiedpersonnel.Connect the PCF3 to the test rig (see test stand sche-matic, Figure 4.4).A. Test Stand Schematic DescriptionV1 Isolation valve, normally open when test is inprogress.V2 Needle valve, regulates pressure into vessel.V3 Vent valve, normally closed when going up on thereceiver pressure; also used to dump pressure fromvessel.V4 Vent valve, normally closed when testing, used asan auxiliary pressure dump valve.P1 Pressure gage, to read dome pressure.P2 Pressure gage, to read vessel pressure.Vessel Receiver Test pressure receiver simulatinga vessel.Dome Receiver Test pressure receiver simulatingthe dome/piston volume on themain valve.In-Line Filter Filters air going into the vessel.

    B. Port Identification and its ConnectionsPort A: Where the pilot control senses the vesselpressure. Connect this to vessel receiver.Port B: Where the pilot control is connected to the domeor piston of the main valve. Connect this to the domereceiver.Port C: The exhaust port, normally vented to theatmosphere (i.e. piped to the outlet of the main valve,with bug screen).

    C. Set Pressure TestingSetting the pilot control is similar to setting a spring-loaded valve where the spring is being compressed tothe desired set pressure. The set pressure is distin-guished by the pop.1. Refer to Table 4.2 for the nominal number of turns

    (on the spring adjusting screw) required to set thevalve. Start counting the number of turns when thespring adjusting screw (approximately) touches theupper spring button (this can be done by feel).

    2. Set the blow down adjuster at its lowest position.3. Pressurize the vessel receiver by slowly opening V2.

    Note: both pressure gages P1 and P2 shall have thesame pressure reading.

    4. Record pop (set) pressure. Note: After pop, P1should drop to zero. If it does not, carefully turn theblow down adjuster up to equalize P1 and P2. Popagain to confirm zero pressure on P1. Overpressur-ize the vessel receiver to 10% or 3 psig, whicheveris greater.

    5. Fine tune the set pressure and blow down to re-quirement (use Table 4.2 as a guide to the numberof turns required).

    6. When the set (pop) pressure on P2 is reached, P1will read zero pressure (main valve is in the open orflowing mode).

    7. Vent the vessel pressure slowly through V3 todetermine the re-seat pressure of the valve. Properre-seat (commonly theres a slurping sound) occurswhen P1 and P2 read the same pressure.

    8. When performance is satisfactory, tighten the locknut, jam nut and cap.

    D. Pilot Seat Tightness TestingA 5/16 OD x 0.035 wall thickness copper tube orequivalent immersed no more than 1/2 deep in watershall be connected to the exhaust port. Raise thereceiver pressure to the test pressure described belowand observe for bubbles. No bubbles are allowed.Test pressure:

    95% of set pressure if set pressure is 100 psigor more OR5 psig below set pressure if set pressure is lessthan 100 psig

    Brush soap and water solution on joints internallyexposed to pressure. Observe for leakage. No leakageat any joint is allowed.E. Test ConclusionVent out pressure from the receiver tank. Unhook all testconnections.If only the pilot control requires maintenance, skipSection V and go on to Section VI for final assembly.


    P1 P2


    V1 V2 V3


    PORT C

    PORT A






    Fig. 4.4 Test Stand Schematic


  • 9Set Spring Spr. Blow Down 95 % ofPressure Number Adj Scr. Adjustment Set

    (psig) (turns) +/- 1/8 (psig)

    15 3 1/2 1/4 1935 B1106 SS 6 1/2 3350 8 1/2 5/8 4851 3 1/2 1/4 4865

    B0125 SS4 1/2 3/8 62

    80 5 1/2 3/8 76100 7 1/2 95101 3 1/2 1/4 96125

    B0530 SS4 1/2 3/8 119

    175 6 1/2 166230 8 1/2 5/8 219231 3 1/4 219280 3 1/2 1/4 266330 4 1/4 314380

    B0531 SS5 3/8 361

    430 5 1/2 3/8 409480 6 1/2 456530 7 1/2 504600 8 5/8 570601 5 3/8 571650 5 1/2 3/8 618700 6 3/8 665760

    B0533 SS6 1/2 1/2 722

    820 7 1/2 779880 7 1/2 1/2 836940 8 5/8 893

    1000 8 1/2 5/8 9501001 5 3/8 9511080 5 1/2 3/8 10261160 6 1/2 11021240 B0535 SS 6 1/2 1/2 11781320 7 1/2 12541400 7 1/2 1/2 13301500 8 5/8 14251501 5 3/4 1/2 14251600 B0536 SS 6 1/4 1/2 15201700 6 3/4 1/2 1615

    Set Spring Spr. Blow Down 95 % ofPressure Number Adj Scr. Adjustment Set

    (psig) (turns) +/- 1/8 (psig)

    1800 7 5/8 17101900 7 1/2 5/8 18052000

    B0536 SS7 3/4 5/8 1900

    2100 7 3/4 5/8 19002200 8 1/2 3/4 20902300 9 3/4 21852301 4 1/2 3/8 21852400 4 3/4 3/8 22802500 5 3/8 23752600 B0403 SS 5 3/8 24702700 5 1/4 3/8 25652800 5 1/2 1/2 26602900 5 3/4 1/2 27552901 4 3/8 27553000 4 3/8 28503100 B0404 SS 4 1/4 3/8 29453200 4 1/4 3/8 30403300 4 1/2 3/8 31353301 3 1/2 1/4 31353400 3 1/2 1/4 32303500 3 1/2 1/4 33253600

    B0210 SS3 3/4 1/4 3420

    3700 3 3/4 3/8 35153800 4 3/8 36103900 4 3/8 37054000 4 1/4 3/8 38004001 3 1/4 38014300 3 1/4 1/4 40854500 3 1/2 1/4 42754700 B0327 SS 3 1/2 1/4 44654900 3 3/4 1/4 46555100 4 3/8 48455300 4 3/8 50355301 3 1/4 1/4 50365500 3 1/4 1/4 52255700 B0415 SS 3 1/2 1/4 54155900 3 1/2 1/4 56056100 3 3/4 1/4 5795

    Pilot Control Spring Chart & Spring Adjusting Screw / Blow Down Adjustments

    Table 4.2


  • 10

    ITEM PART NAME MATERIAL1 Body SA-216, GR. WCB, CARB. ST.2 Nozzle 316 ST. ST.3 Retainer Screw 316 ST. ST.4 Seat Retainer 316 ST. ST.5 Piston 316 ST. ST.6 Return Spring 316 ST. ST.7 Guide/Cover 316 ST. ST.8 Body Studs ASTM A193 GR. B79 Body Hex Nut ASTM A194 GR. 2H

    10 Male Elbow 316 ST. ST.11 Tubing 316 ST. ST.12 Sensing Nipple 316 ST. ST.13 Nozzle Seal Viton

    14 Seat Seal Viton

    15 Piston Seal Viton

    16 Cover Seal Viton

    17 NPT- Tub Connector 316 ST. ST.


    1 Body SA-216, GR. WCB, CARB. ST.2 Nozzle 316 ST. ST.3 Retainer Screw 316 ST. ST.4 Seat Retainer 316 ST. ST.5 Piston 316 ST. ST.6 Return Spring 316 ST. ST.7 Cover 316 ST. ST.8 Guide 316 ST. ST.9 Body Studs ASTM A193 GR. B7

    10 Body Hex Nut ASTM A194 GR. 2H11 Male Elbow 316 ST. ST.12 Tubing 316 ST. ST.13 Sensing Nipple 316 ST. ST.14 Nozzle Seal Viton

    15 Seat Seal Viton

    16 Piston Seal Viton

    17 Cover Seal Viton

    18 Guide Seal Viton

    19 NPT- Tub Connector 316 ST. ST.

    Fig. 5.1Main Valve (1, 1 1/2, & 2 Inlet)

    Fig. 5.2Main Valve (3, 4, 6 & 8 Inlet)

    Viton is a registered trademark of DuPont Dow Elastomers










    1511106 798



















    V. Main Valve


  • 11


    1 Wrenches 1/2, 5/8, 3/4, 7/8, 1-1/42 O-Ring Pick3 1 Square Drive 1-5/8, 2-7/16,

    Socket Spanner 2-1/2, & 3-5/84 1-1/2 Square Drive 4-1/2

    Socket Spanner5 Screw Driver6 Wire Cutter7 Extension Bar 9, 18

    8 C-Clamp9 Eye Bolt

    *Special tool for 6 & 8 inlet size valves (Part #s 25678and 25677 respectively).

    For 1, 1-1/2 and 2 inlet size: (Figure 5.1)1. Place valve on a clean and well-lit workbench.2. Remove wire seal.3. Remove pilot control, bracket and interconnecting tubing.4. Do not remove sensing nipple from body.5. Loosen body hex nuts and remove from cover.6. Using a nipple in the guide connection, carefully lift

    the guide-piston assembly straight up. Avoid tilting ordropping, which could damage nozzle face.

    7. Invert the guide-piston assembly and slide thepiston and spring out.

    8. Remove cover seal.9. Remove seat retainer from piston by unscrewing the

    set screw.10. Remove seat seal and piston seal with o-ring pick.11. Unscrew nozzle from body with a socket spanner.12. Remove nozzle seal.For 3, 4, 6 and 8 inlet size: (Figure 5.2)1. Place valve on a clean and well-lit workbench.2. Remove wire seal.3. Remove pilot control, bracket and interconnecting tubing.4. Do not remove sensing nipple from body.

    5. Loosen body hex nuts and remove from cover.6. Lift cover using eyebolts and lifting device.7. Remove spring.8. Remove cover seal from top of guide.9. Remove piston from guide using eyebolt and lifting

    device. Guide may also be lifted along due to pistonseal friction. Hold the guide so that it will not be liftedwith the piston.

    10. Remove guide and guide seal from body.11. Unscrew set screw to remove seat retainer from piston.12. Remove piston seal and seat seal.13. Unscrew nozzle from body with socket spanner or

    special tool. Remove nozzle from body.14. Remove nozzle seal from body.

    (ii) Cleaning and RepairingClean all parts thoroughly. Replace all o-rings. Inspect allparts and replace any that are worn. NO REMACHININGIS ALLOWED. Polish guiding surfaces, if required. Foro-ring purchasing, be sure to specify original compound.If in doubt, contact the Farris Factory.

    (iii) AssemblyFor 1, 1-1/2 and 2 inlet size:

    1. Refer to Figure 5.1 for construction details.2. Visually inspect all parts to be assembled. Replace

    any parts that are worn or damaged.3. Lubricate all threaded and mating surfaces with

    Bostik Never Seez or equivalent.4. Lubricate all seals with grease compound that is

    compatible to the elastomer.5. Insert nozzle seal into recess on bottom of nozzle.6. Screw nozzle into body using socket spanner.7. Position piston with the seat facing up. Place seat

    seal on piston, making sure it fits evenly and sym-metrically.

    8. Place seat retainer on piston and tighten set screw,making sure that seat retainer sits evenly andsymmetrically on piston. Use C-clamp to hold thepiston and retainer in order to tighten the setscrew fully.

    9. Insert piston seal into the groove around the circum-ference of the piston.

    10. Place cover seal onto the body.11. Invert piston so that the seat retainer faces down.

    Place spring on top of piston. Insert piston into guidewith the spring in between. Check manually if thereis interference between the guide and the piston.There may be some resistance due to the pistonseal and the spring.

    12. Carefully place the guide-piston assembly intothe body.

    Fig. 5.3Sample Nameplate for Main Valve

    32HC10-1201 1/2 H 3 100 PSIG

    17141234-DX PSV - 100



  • 13. Thread body hex nuts onto body studs and tighten.14. If sensing nipple is removed from the body, thread it

    to the body and make sure the hole orientation iscorrect and agrees with the arrows marked (Refer toFigure 5.4).

    15. The main valve is now ready for final assembly (SeeSection VI).

    For 3, 4, 6 and 8 inlet size:

    1. Refer to Figure 5.2 for construction details.2. Follow steps 2-5 of the assembly procedure for 1,

    1-1/2 and 2 main valves.3. Screw nozzle into body with socket spanner. Use the

    special tool to tighten nozzle for 6 and 8 inlet sizevalves.

    4. Place the guide seal onto the body.5. Place guide into the body carefully. Make sure that

    guide is seated on the body evenly.6. Position piston with the seat facing up. Place seat

    seal on piston, making sure it fits evenly.7. Place seat retainer on piston and align the holes of

    retainer to the threaded holes on piston. Tighten setscrews. Use C-clamp to hold the piston and retainerif necessary.

    8. Insert piston seal into the groove around the circum-ference of the piston.

    9. Invert piston so that the retainer faces down. Liftpiston with eyebolt and lifting device, and lower it intothe guide carefully. Push the piston into the guide ifneeded. There should not be any interference be-tween the guide and the piston, but there may besome frictional resistance caused by the piston seal.

    10. Place spring on top of piston.11. Place cover seal on guide.12. Lift cover with eyebolts and lifting device. Align the

    holes of the cover with the body studs. Lower coverover guide.

    13. Thread body hex nuts onto body studs and tighten.

    14. If sensing nipple is removed from the body, thread itto the body, making sure that hole orientation iscorrect and agrees with the arrow marked (Refer toFigure 5.4).

    15. The main valve is now ready for final assembly (SeeSection VI).

    VI. Final AssemblyThe pilot control should have been tested and set priorto final assembly.Assemble the pilot control to the main valve. Attach themounting bracket securely to the pilot control. Bolt themounting bracket to the main valve. Clear foreign matterin tubing by blowing compressed air through one end.The port connection and its orientation shall be exactlythe same as the original configuration to guaranteevalve operation. Refer to Figure 4.1 for port identificationof the pilot control. Connect port A of the pilot control tothe inlet of the main valve. Connect port B of the pilotcontrol to the dome or piston of the main valve. Port C isthe exhaust port, normally vented to the atmosphere.Test the assembled pilot valve for proper setting.Next, perform leakage test on the pilot valve.

    Main Seat Tightness Test (Refer to Figure 6.1)Mount bubble test flange, tube, and cup on valve outlet.A tube of 5/16 OD X .035 wall submerged 1/2 belowthe water level shall be connected to the valve outlet.Apply nitrogen or air pressure to the valve inlet, equal to95% of set pressure (if set pressure is 100 psig or more)or 5 psig below set pressure (if set pressureis less than 100 psig). This method testsfor total leakage across valve seat pluspiston seal leakage. No leakage is allowed.The valve is now readyto be placed backin service.

    R1 10/99 1M

    IMPORTANT!Arrows should pointdownward as shown forproper functioning of thepilot valve.


    High Pressure Source(Air or Nitrogen)

    Pressure Regulator


    Vent Valve




    Port B

    Port A

    Port C

    Fig. 5.4 Sensing Nipple Orientation

    Fig. 6.1Main Seat

    Tightness Test