GV Series Repair Instructions

Peter Skop Industries

Compressed Gas Division

Sherwood® GV & GVA Series Valve Repair Instructions

As a Stocking Distributor, PSI can quickly ship a large selection of Sherwood Compressed Gas Products from our inventory.

“GV” Series Industrial & Chrome Plated Cylinder Valves

Repair Instructions

Disassembly:

Place the valve assembly into a vise or similar holding fixture. Do not damage the inlet and outlet threads. The holding fixture must securely grip the valve body on the wrench flats so no damage is done to the internal bores, external threads, outlet, or pressure relief device.

A. Chamber

1. Using a 13 mm socket, remove the lock nut from the handwheel by turning it counter clockwise.

2. Remove the handwheel from the stem square.

3. Using an 11/16” socket wrench or hex box wrench, remove the bonnet by turning it counter clockwise. The stem subassembly with o-ring and back-up ring may remove with the bonnet. If not, remove the stem subassembly from the valve after the bonnet.

4. Being careful not to scratch the bonnet sealing surface in the valve body, use a square drive to remove the lower plug from the valve chamber, by turning it counter clockwise.

B. PRESSURE RELIEF DEVICE

1. Being careful not to scratch the pressure relief device sealing surface in the valve body, remove pressure relief device by turning it counter clockwise using a 5/8” hex box wrench or socket.

Inspection of Valve Components:

1. Valve Body-inspect the valve body chamber for dirt, debris, and damage.

a. Where possible, blow out the valve body chamber using clean, dry compressed air or Nitrogen to remove any foreign particles.

b. If the valve body is damaged, do not attempt to repair. Order a new valve assembly.

2. Bonnet/Stem Subassembly- always discard.

3. Lower plug-always discard.

4. Handwheel-if damaged, discard.

5. Pressure Relief Device-inspect threads for damage and inspect disc and washer for scratches or damage. If damaged, discard.

Assembly:

A. CHAMBER

1. Apply 3 dabs of lubricant around the perimeter of the lower plug threads, approximately the size of a pencil eraser each. Locate lubricant toward the lower most threads closest to the crimped seat. Be careful not get lubricant on nylon seat. IMPORTANT: Use Turmoxygen LC027 lubricant for oxygen service. Use Christo-Lube, MCG -111, lubricant for all other gas applications.

NOTE:

1 The lower plug being replaced must correspond with the valve body and its relative application. For example, standard cylinder valves have a .125” through hole in the body, which has a nylon seat diameter that is relative to that size, part number 1400-40. Carbon dioxide and manifold valves, typically have a .272” through hole in the body with a nylon seat that is relative to that size as well, part number 1400-40A. Please contact the manufacturer if there is any question what the appropriate part number is based on the valve being repaired.

2. Being careful not to damage the bonnet sealing surface in the valve body, install the new lower plug into the chamber, seat first and tighten using a square drive until it is fully seated.

3. Place new bonnet & stem subassembly into valve body. Hand tighten bonnet by turning it clockwise. Rotate stem square until it becomes engaged in the lower plug.

4. Using an 11/16” hex torque wrench tighten bonnet to 50 – 60 ft-lbs.

Note: a properly calibrated torque wrench must be used to tighten the bonnet. Over tightening will damage the bonnet.

5. Place the handwheel over the square on the stem. Thread the lock nut onto the stem thread then, tighten to 15-30 in-lbs.

6. To ensure free and smooth operation, open and close the valve several times by turning the handwheel.

B. PRESSURE RELIEF DEVICE (PRD)

Note: Refer to CGA S-1.1 latest edition to select correct pressure relief device type for the cylinder and application.

1. Thread the proper pressure relief device into the PRD port until hand tight.

2. Using a 5/8” socket and a torque wrench, tighten the PRD to 25-35 ft-lb.

Note: a properly calibrated torque wrench must be used to tighten the bonnet. Over tightening will damage the PRD.

Testing of Assembled Valve:

1. Thoroughly test each repaired valve assembly by inserting and tightening the valve assembly into a cylinder or suitable test fixture. Pressurizes the valve assembly with an inert gas to the working pressure of the cylinder of intended use.

2. With outlet suitably plugged, open the valve assembly by turning the handwheel counter clockwise. Check the bonnet, stem, and pressure relief device areas for leaks using proper leak detection solution or leak detection equipment.

3. Close the valve assembly by turning the handwheel clockwise. Remove the outlet plug and check for seat leakage through the outlet using proper leak detection solution or leak detection equipment.

4. If any leakage is detected, in the open or closed position, make necessary repairs before using the valve assembly.