How to Repair the 30 HPG Valve Pilot

The HPG Valve Pilot is used to modulate an output pneumatic signal when the monitored pressure changes in relation to the desired set point.  

Maintenance should be performed every 12 months.  In this video, Carlos shows you how. 

Repair Tools Needed

Here are tools you will need:  

  • 9/16 wrench 
  • 9/16 socket wrench 
  • 11/16 wrench 
  • Pick 
  • Channel locks 
  • Crescent wrench 
  • 5/8 wrench 
  • Loc-Tite 
  • And a lubricant 

How to Disassemble the Pressure Pilot

Before performing any service, verify all system pressures are bled-off or the pilot is properly isolated and de-pressurized.  

Start by mounting the pilot into the vice by the filter body. 


  • Unscrew the adjustment screw counter-clockwise until the spring is completely unloaded.
  • Remove and discard the washer and packing seal.
  • Remove the both breather plugs and set aside.


  • Loosen the pressure gauge with a 9/16 wrench and remove it. 


  • Using a back-up wrench, loosen the 4 main housing bolts.  


  • Lift the bonnet off the upper housing.  
  • Remove the spring plate, spring, and second spring plate and set them aside. 


  • Separate the housings from the base. If it’s stuck, you may need to use a screwdriver or a pick to separate the parts.  
  • Unscrew the 113 seat from the lower housing.
  • Remove the seat and diaphragm and discard them both – Replacements are included in the rebuild kit.
  • Separate the two housings.
  • Remove the spacer ring and set aside. 
  • Wrench loose the seat extension and discard the diaphragm. 
  • Set the diaphragm plate aside.
  • Wrench loose the seat extension and set it aside.  
  • Remove and discard the diaphragm. 
  • Set the diaphragm plate assembly aside. We will disassemble this in the vise later. 


  • Remove the spring from the top of the seat and discard. This is sometimes called a “booster spring”. 
  •  Loosen the seat with a socket wrench and discard the seat assembly 
  • Remove and discard the spring from the base 
  • Adjust the base in the vice and use a wrench to remove the filter cap from the body.  
  • Discard the O-ring from the cap 
  • Use a pick to remove the filter screens. If that doesn’t work, you can use pliers or insert a punch or screwdriver in the plug hole to remove the filter screens.  
  • Remove assembly from vise. If air is available, apply air pressure where you removed the spring. Make sure that the open side of the filter body is not facing you. This will remove most debris out of the filter body. If there is still a restriction of air, you will need to remove it before reassembling the valve.  
  • Set the diaphragm plate in the vise.  
  • Remove the diaphragm nut with channel locks and set it aside.
  • Remove and discard the diaphragm from the plate. 
  • If you’re doing this repair in the field, this is as far as you need to disassemble.  
  • If you’re planning to sandblast this in a repair shop, remove the nipple/filter assembly and set aside.  

Inspection and Cleaning 

After disassembly, we recommend sandblasting and thoroughly cleaning the metal surfaces. This helps restore your pilot and allows for a proper inspection. 

It’s very important to completely remove all debris from sandblasting. Any contamination in the pilot area can cause a malfunction. 

Use wire brushes to clean the threads.


  • Filter Body 
  • Housing NPT’s 
  • Base 
  • Bonnet 
  • Diaphragm Nut 
  • Bolts 


Use compressed air to remove any debris: 

  • The sense port in the upper housing and tee 
  • the vent port in the lower body  
  • the bonnet (including the adjustment screw threads)  
  • the upper seat threads in the lower body 
  • the filter body (attention should be paid to cap and nipple threads) 
  • the diaphragm nut  



  • Put the 116 diaphragm plate into the vise.
  • Install the 5259P diaphragm onto the diaphragm plate.
  • Thread the 107 diaphragm nut onto the diaphragm plate.
  • Add the diaphragm ring (7437).
  • Tighten the 107 nut with channel locks verifying that you don’t go beyond the ring.
  • Remove the assembly and put the filter body in to the vise.


  • Install the new filter screens one by one into the filter body.
  • Install the O-ring on the filter cap adding a small amount of lubrication. 
  • Tighten it on the filter body with a wrench.
  • If you have disassembled the base from the npt, when you’re putting it back together, it is VERY IMPORTANT to verify that the drill hole is in the lower position in the base for the correct supply connection. 
  • Thread the base into the filter with the npt. Make sure the 699 plug is facing the same direction as the base.  


  • Install the #108 spring “wide” end first.
  • Install the 118 gasket onto the shoulder of the 565 seat.
  • Then insert the pilot plug “small ball” first through the seat.
  • Using the small ball of the pilot plug as a handle, thread the seat into the base.
  • Torque the seat down using a 9/16th socket. 
  • Install the #566 booster spring into the seat.


  • Install the upper #113 seat through the #110 diaphragm and set aside.
  • Install the seat extension through the center hole of the 110 Diaphragm.
  • Then install the diaphragm assembly into the 1701 housing with the tee attached.
  • Install the seat extension onto the diaphragm plate by hand.
  • Using a wrench or nut driver, tighten snug.
  • Apply pressure on the diaphragm plate to prevent spinning.
  • Install the spacer onto the upper housing, with the numbers facing up.
  • Verify the diaphragm remains centered and flat as the edges may cut Diaphragm.
  • Put on the lower housing.
  • Install the upper #113 seat and #110 diaphragm assembly into the housing.
  • Using a wrench or nut driver, tighten snug the seat and verify that the diaphragm has not been damaged.
  • Place the two connected housings onto the base and verify that the 110 diaphragm is seated evenly. The spring must sit into the groove machined into the seat. 
  • The tee should be facing the back of the filter body and the breather plug opening facing the same direction as the filter body cap. 
  • Put on the 7437 diaphragm ring.
  • Apply grease to the diaphragm plate.
  • Place the 2612 spring plate onto the diaphragm assembly.
  • Then put the 2611 spring onto the spring plate.
  • Place the other spring plate on top and apply more grease. 
  • Install the bonnet, taking care that the spring assembly remains intact. 
  • The breather plug opening should be opposite of the filter body.
  • Replace the four bolts and nuts and tighten.
  • If you have a newer pilot, all the bolts should be the same length. If you have an older style pilot, the short bolts will face the tee.  


  • Apply lock-tight and use a 9/16 wrench to tighten the pressure gauge into the tee. 
  • Install the breather plugs with a wrench, with the hole facing down to prevent moisture or debris from entering the pilot.
  • Lastly, install the adjusting screw with the new washer, packing seal and a small amount of lubrication.

Still Need Help?

 If you need help repairing your pilot or any other Kimray product, contact your local Kimray store or authorized distributor.