ISOLATE A NONADJUSTABLE PRESSURE RELIEF VALVE MALFUNCTION
When you are performing the nonadjustable pressure relief valve "pop-off" test,
the nonadjustable pressure relief valve may stick or operate intermittently. If this
happens, you must trouble-shoot for the malfunction. Refer to figure 3-3.
No repair should ever be undertaken or attempted by anyone who is not
trained in repairing devices of this nature.
Figure 3-3. Control head.
a. Place a small screwdriver through one of the vent holes and carefully attempt
to un-stick the valve.
b. Disassemble the valve for cleaning and repair if the valve continues to stick or
(1) Disassemble the pressure relief valve. Inspect the parts for wear and/or
damage during disassembly.
(a) Remove the Tru-arc retaining ring.
(b) Remove the cap.
Remove the compression spring.
(d) Remove the pressure relief valve stem.
(e) Remove the pressure relief valve body.
Remove the gasket.