In this guide we’ll walk you through everything there is to know about pilots and relays.
From the basics of how it works to step-by-step repairs and troubleshooting, you’ll gain a solid foundation of knowledge on how to operate and maintain Kimray’s pilots and relays.
Use the table of contents to skip to different sections of the learning path.
1. How to Repair and Maintain a Diaphragm Controlled High Pressure Pilot
The Diaphragm Controlled High Pressure 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.
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
Lubricant
How to Disassemble a Diaphragm Controlled High 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.
Step 1: Adjustment Screw
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.
Step 2: Pressure Gauge
Loosen the pressure gauge with a 9/16 wrench and remove it.
Step 3: Housing Bolts
Using a back-up wrench, loosen the 4 main housing bolts.
Step 4: Bonnet
Lift the bonnet off the upper housing.
Remove the spring plate, spring, and second spring plate and set them aside.
Step 5: Body
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.
Step 6: Base
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.
How to Inspect and Clean a Diaphragm Controlled High Pressure Pilot
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.
Threads
Filter Body
Housing NPT’s
Base
Bonnet
Diaphragm Nut
Bolts
Body
Use compressed air to remove any debris:
Sense Port in the Upper Housing and Tee
Vent Port in the Lower Body
Bonnet (Including the Adjustment Screw Threads)
Upper Seat Threads in the Lower Body
Filter Body (Pay particular attention to Cap and Nipple Threads)
Diaphragm Nut
How to Reassemble a Diaphragm Controlled High Pressure Pilot
Step 1: Diaphragm
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.
Step 2: Filter Body
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.
Step 3: 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.
Step 4: Housing
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.
Step 5: Gauge & Adjusting Screw
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.
2. How to Convert a Bellows-Controlled Pressure Pilot
A pressure pilot is used to monitor and control upstream or downstream pressure between 75 and 2500 PSI. It does this by pneumatically positioning a control valve to achieve your desired set point.
The Kimray Bellows Controlled Pressure Pilot is modular, versatile, and easy-to-use in several applications. Part of its value is that it can act in either direct or indirect mode with simple modifications.
2.1 Direct vs Indirect
Scenario 1: How to Change the Bellows for a Different Operating Pressure
In the bellows controlled pressure pilot, the bellows itself can be changed to better suit your operating conditions. This could be useful if you were previously using a 250 pilot and now needed to control pressures below 200 PSI. For this scenario, we’re going to convert a 250 Pilot to a 75 Pilot which will then operate from 75 to 750 PSI.
2.2 Pilot Bellows2.3 Changing Operating Pressure
The same process can be used to convert a 75 pilot to a 250 pilot, but you will also need to have a (6522) spring ready to install.
Before performing any service, make sure the valve is isolated from all gas sources and that the valve package operating and instrument gas lines are completely depressurized. Never loosen any fittings or valve connections while there is pressure in the lines.
2.4 Tools and Parts Needed
To begin, make a mark on the pilot so that aligning the components will be easier later during assembly.
Next, remove the adjustment bolt. The goal is to remove spring tension. You can either take it all the way out or back it out to the point where you can start unthreading it by hand.
With the valve package isolated from all gas sources, disconnect the tubing.
Using a 9/16” and 11/16” wrench, remove the bracket bolts to separate the pilot and bracket from the high pressure control valve package.
Turn the pilot upside down and secure it in a vise.
Use a 9/16” wrench to remove the four screws from the body.
Separate the lower housing and the pilot and set them aside.
Remove the diaphragm plate from the bonnet. If it’s stuck, use a flat-headed screwdriver to remove it.
Remove the spring plate and inner spring from the bonnet.
Replace the spring plate and add grease if necessary.
Replace the diaphragm plate and the pilot, using your markings to make sure it’s aligned.
To replace the bellows assembly, first remove the lower housing from the main body.
Unthread and remove the bellows. If it doesn’t come off easily, use a rag for a better grip. If necessary, use channel locks, but be careful not to damage the assembly.
Carefully remove the (265) O-ring on the bellows. This will need to be reused on the new assembly, so be careful not to damage it.
It’s also a good idea to inspect the O-ring on the main body. If there is damage, the RBQ repair kit will include replacements for all soft goods.
Roll the O-ring over the threads to install it on new bellows assembly (5148).
Thread the new bellows into the lower housing by hand.
Then reinstall the housing on the main body, pushing down with your hand, and make sure to align the markings.
Using your markings, align the bonnet, pilot, housing and body. The inlets and outlets will be 90 degrees from the vent port.
Replace the screws and bracket and tighten with a crisscross pattern, evenly distributing pressure as you tighten.
In this scenario the pressure range is now between 75 to 750 PSI. The original gauge will work for this pressure range but may be difficult to view accurately. You may want to purchase the appropriate (7708) pressure gauge instead. If you were converting this from a 75 to a 250 Pilot, you would need to purchase a (7710) 2500 PSIG gauge in order to operate it.
Reattach the pilot to the control valve and install your tubing.
2.5 Pressure Ranges on Gauges
How to Convert a Bellows Controlled Pressure Pilot from Indirect to Direct Acting
Another way that the pressure pilot is modular is that it can be configured for indirect or direct acting actuation.
2.6 Indirect to Direct
The standard set up for a back pressure valve’s fail position is fail open, which would mean the pilot would be indirect acting.
With indirect acting mode, an increase in sense pressure will decrease output pressure to the valve, while a decrease in sense pressure will increase output to the valve.
With direct acting mode, an increase in sense pressure will increase output pressure to the valve, while a decrease in sense pressure will decrease output to the valve.
Begin the same way previously shown for changing the bellows assembly:
To begin, make a mark on the pilot so that during assembling the components will be easier to correctly align.
With the level controller isolated from all gas sources, disconnect the tubing.
Using a 9/16” and 11/16”, remove the bracket bolts to separate the pilot and bracket from the high pressure control valve package.
Next, remove the adjustment bolt. The goal is to remove spring tension. You can either take it all the way out or back it out to the point where you can start unthreading it with your hand.
Turn the pilot upside down and secure it in a vise.
Use a 9/16” wrench to remove the four screws from the body.
Separate the lower housing and main body from the pilot.
Separate the pilot from the bonnet and set aside.
Remove both diaphragm plates. If they are stuck, use a flat-headed screwdriver to remove them.
The two diaphragm plates have different inner diameters. To differentiate between them, look at the grooves on the diaphragms. The width of the diaphragm grooves will match the width of the plate grooves.
2.7 Diaphragm Plates
Replace the diaphragm plates on the correct diaphragms.
Holding the pilot and plates in place, FLIP the unit 180 degrees and place it back on the bonnet.
In this instance we are only changing the action of the pilot, so this is as much as required for disassembly.
Using your markings, align the bonnet, pilot, housing and body. Align the sense holes with the supply and output holes. The inlets and outlets will be 90 degrees from the vent port.
Replace the screws and bracket and tighten with a crisscross pattern, evenly distributing pressure as you tighten.
At this point, the pilot is ready to be attached to the control valve. However, if the pilot action is changing, the valve fail position will also need to be changed. This will affect the tubing connections for the pilot output and pilot sense line.
When all the components are configured correctly to work together, put the adjustment screw back into the pressure pilot and adjust it accordingly.
