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Temperature and Spring Pilot Combination

1. Install the temperature pilot next to the main valve.

2. Install a 1/4" NPT nipple between the outlet tapping 

port of the temperature pilot and the inlet port of the 
spring pilot.

3. The 1/4" feedback tapping port of the spring pilot 

must be connected to the downstream piping:

• Use 1/4

black steel pipe

for the feedback line.

• Install a 1/4 NPT shut off valve and union in the 

feedback line to allow service of the pilot while 
operating the system on the by-pass line.

• The feedback line 

must

pitch away from the pilot to 

avoid erratic operation and excessive fouling and to 
eliminate water pockets.

4. When the regulator is used with a heat exchanger, 

connect the feedback line (B) (see illustration on 
page 6 to the heat exchanger shell.  A tee fitting can 
be installed in the heat exchanger for a vacuum 
breaker connection.

5. Insert the sensing bulb of the temperature pilot so the 

full length of the bulb is exposed to the fluid whose 
temperature is being controlled. 

a) Use a 1/2 NPT compression fitting to install the 

bulb at the outlet of instantaneous heaters and in 
the middle of storage tanks. 

b) The preferred bulb mounting when installed in the 

system piping is illustrated on page 7.

c) Optional dry well (separable socket) allows the 

sensing bulb to be removed from the tank or piping 
without draining the system.  

• When using a dry well, coat the bulb with high 

temperature grease or heat transfer compound, 
to aid heat transfer.

• Make sure that bulb and dry well are fully inserted

into the fluid being controlled.

Spring Pilot

Outlet

Balance Tube

Self-Contained
Temperature
Pilot

Bleed
Orifice

Main Valve
Inlet

Pilot Inlet

Pneumatic Temperature and Air Pilot
Combination

Series 315 PNT Pilot

Series 240 PNT Pilot

1. Connect a regulated air supply to the "Reverse 

Acting" inlet port of the 315 PNT pneumatic 
temperature pilot.

2. Do not plug the "Direct Acting" inlet port of the 

pneumatic temperature pilot.  This port serves as 
an air bleed.

3. Connect the output "Signal" port of the pneumatic 

temperature pilot to the top of the AP-1A or AP-4A 
pneumatic air pilot.

1. Connect a regulated air supply to the "Supply Air" 

port of the 240 PNT pneumatic temperature pilot.

2. Connect the output "Branch Air" port of the pneumatic

temperature pilot to the top of the AP-1A or AP-4A 
pneumatic air pilot.

Air Supply

Feedback Line

Balance
Tube

Outlet

Bleed
Orifice

Main Valve
Inlet

Pilot Inlet

Signal

AP Air 
Pilot

Temperature
Sensor

315 PNT

Temperature

Pilot

Air PRV
Regulator

High Pressure
Supply Air

Main

Branch

Supply
Air Port

Branch
Air Port

y

y

y

y

y

y

y

y

y

y

y

y

y

y

y

y

yy

yy

y

y

y

y

y

y

y

y

y

y

y

y

y

y

y

y

yyy

yyy

yy

yy

yy

yyy

yyy

yy

yy

y

y

y

yy

y

yy

yy

y

y

y

y

y

yy

yy

yy

y

y

y

y

y

y

y

y

y

y

y

Signal Port

Reverse Acting
Signal Port

1/2" NPT

Direct Acting
Signal Port

8

Summary of Contents for Bell & Gossett Hoffman Specialty 2000 Series

Page 1: ...INSTRUCTION MANUAL HS 601I 510549...

Page 2: ...lots only The steam system relief valve opening set point pressure is based on the supply steam inlet pressure to the regulator and must be set as follows 12 Locate temperature regulators close to the...

Page 3: ...ee siphon loop tube petcock and pressure gauge 12 On NPT sized regulator valves install a pipe union M to allow regulator removal for service or replacement 13 Use compressed air or steam to clean pip...

Page 4: ...d directly into the heat exchanger shell 22 Install pressure relief valve V in the downstream piping as required by codes 23 Install a tee fitting W for pressure feedback line 24 Install a siphon loop...

Page 5: ...254 5 7 145 Combination 2 1 2 65 10 6 269 12 8 325 10 0 254 5 9 150 Pilots 3 80 11 2 284 13 1 333 10 0 254 6 4 162 4 100 13 0 330 13 9 353 10 0 254 7 9 200 6 150 16 6 422 14 9 378 10 0 254 9 5 241 1...

Page 6: ...n 6 Install the L fitting from the hardware kit in the tapping at the center of the main valve diaphragm cover Note For steps 7 and 8 trim the length of the copper tubing as required see Tubing Length...

Page 7: ...t 1 When only a temperature pilot is used the outlet tapping port must be reduced Use the 1 8 x 1 4 NPT bushing from the hardware kit in the 1 4 NPT outlet 2 Insert the sensing bulb so the full length...

Page 8: ...from the tank or piping without draining the system When using a dry well coat the bulb with high temperature grease or heat transfer compound to aid heat transfer Make sure that bulb and dry well ar...

Page 9: ...ediate pressures can be interpolated from the chart PNT Air Signal Maximum Steam Pressure from Main Valve Outlet Pressure AP 1A Pressure Pilot AP 4A Pressure Pilot psig Bar psig Bar psig Bar 9 0 62 0...

Page 10: ...radually compress adjusting spring by tightening adjusting nuts equally until the pilot valve opens Air Adjust Air PRV to allow pressure to build slightly until the air pilot valve opens Temperature I...

Page 11: ...making the adjustment 4 Observe the temperature while the system is running 5 Adjust the sleeve until the desired temperature is reached 6 Tighten the dial set screw without turning the adjusting sle...

Page 12: ...e Cause Low inlet pressure Solution Correct supply pressure from the boiler Fully open supply valve Check for upstream blockage Cause The regulator is not properly adjusted Solution Readjust the pilot...

Page 13: ...e air line slowly increase the air pressure on the main valve diaphragms from 0 psig to 30 psig 0 to 2 1 bar Slowly decrease the pressure back to 0 psig 0 bar Repeat this step several times 4 Check fo...

Page 14: ...Valve Seat Lapping Procedures below 9 To continue disassembly Replace plug and stem nut onto stem to prevent damage to diaphragm when air pressure is released Do not fully tighten nut Relieve air pres...

Page 15: ...necessary or replace components to stop any leaks 15 Return the main valve to service Main Valve Diaphragm Replacement A leak in the diaphragm will not allow full steam pressure to build up under the...

Page 16: ...t 7 Connect a 30 psig air supply to the 1 4 NPT pilot INLET port 8 Test for seat and disc leakage Open shut off valve from SIGNAL LINE port Apply air pressure at the INLET port Check for leakage from...

Page 17: ...ding the stem Spring Pilot Seat Lapping Operations Lap sparingly using 500 grit lapping compound and light pressure Heavy grinding may cause galling wide sealing surfaces and a grooved disc all of whi...

Page 18: ...urns 3 Back off air loading pressure 4 If used in conjunction with a temperature pilot set temperature setting higher than the bulb temperature 5 Slightly open the shut off valve in the steam supply t...

Page 19: ...If air is leaking replace the diaphragms AP 4A With a 30 psig air supply to the FEEDBACK tapping the SIGNAL line and IN tapings plugged check for air leakage from the vent hole of the pilot If air is...

Page 20: ...ble well is provided Failure to follow this procedure may result in serious burns CAUTION Temperature pilot bulb will be inserted in the heated fluid Before immersing check compatibility of copper bul...

Page 21: ...ecessary 4 Apply non hardening sealant to bottom plug 4 threads Reassemble pilot 5 Retest pilot y y y yy y yy yy yy yyy y y y yy y y y y y y yy yy yy yy yy 150 F 70 C 60 C 50 C 125 F BELLOWS HOUSING B...

Page 22: ...achieve the desired system temperature 3 Allow system temperature to stabilize at the desired set point temperature and normal load conditions Securely tighten the adjustment knob set screw 4 Rotate...

Page 23: ...lect alteration accident or physical damage c used in a manner contrary to Seller s instructions for installation operation and maintenance d damaged from ordinary wear and tear corrosion or chemical...

Page 24: ...ration and maintenance d damaged from ordinary wear and tear corrosion or chemical attack e damaged due to abnormal conditions vibration failure to properly prime or operation without flow f damaged d...

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