Farris Engineering Valve 27DA23-120/S4

Remove wire seal and slide out button head rivet

Remove set screw from base of cap and lift cap off bonnet

Hold the stem with pliers and remove stem jam nut and stem test washer

Reassemble all parts in reverse order

Packed Lifting Lever Disassembly

Check applicability of backpressure test

Test secondary pressure zone for valves exceeding 1" inlet size

Verify tightness of gasket joints and vent/drain plugs

Rework valve if leakage is detected

Use appropriate test fluid as shown in Table 2

Mount valve on test stand and note set pressure and CDTP

Hold the stem tightly and tighten spring adjusting screw clockwise

Slowly raise test drum pressure and observe the opening (set) pressure

Is the set pressure within +/-3% tolerance?

Reduce test drum pressure 25% below opening pressure if necessary and adjust spring adjusting screw

Pop valve once more to ensure set pressure adjustment was not disturbed

Mount the valve on the test stand

Attach a blind test fixture for air, gas & vapor service valves

Enter the cold differential test pressure (CDTP)

Enter the test pressure to be held

Leakage Test for Air, Gas & Vapor Service Valves

Verify all parts required for assembly are grouped

Visually inspect all parts for imperfections and cleanliness

Check guide for dirt or scale in exit holes and undercuts

Lubricate all threaded surfaces with Bostik Never-Seez or equivalent

Lightly coat sealing surfaces with pipe thread sealant

Ensure sliding and bearing surfaces are clean and assembled without lubricants

Place disc in disc holder with V-notch facing stem radius

Insert assembly into guide and install body gasket on the body