4-27. PRESSURE REGULATING VALVE REPAIR - cont.
To prevent premature failure of diaphragm, nut must be tight If nut is loose on stem, diaphragm
could pull loose and tear under pressure.
(7) Install diaphragm (10), diaphragm washer (9) and nut (8) on stem (15). Tighten nut until
diaphragm cannot be twisted on stem.
(8) Check compression of disc (12) between disc guide (14) and disc retainer (11). Disc should be
compressed very lightly. If disc is deformed, install additional spacer washers (13) between disc
guide and disc retainer as required.
To prevent damage to stem or seat, lower stem straight into seat (16).
(9) Lower assembled diaphragm (5) into body (20). Make sure end of stem (
15) mates correctly with
(10) Align holes in diaphragm (10) with studs on body (20). If required, diaphragm may be
stretched to fit over studs.
(11) If removed, install bearing (6) in cover (4).
(12) Install spring (7) on stem (15).
(13) If removed, install cover bearing (6) in cover (4)
To prevent damage to bearing cover or valve stem, cover must be lowered straight onto stem
without twisting or binding.
(14) While matching alignment marks made during disassembly, lower cover (4) over stem (15) and
onto valve body (20).
(15) Install eight nuts (1) on cover (4) until handtight.
Assemble Bypass Piping. Refer to figure 4-21.
Ensure that anti-seize tape is applied in the same direction as the threads.
(16) Apply anti-seize tape to male threads of nipples (5, 7, 12, 14, 16, 18 and 22), elbows (9 and 20),
bushings (19 and 23), connector (3) and restrictor (10).
(17) Screw bushing (23) and 1-inch nipple (22) onto pressure regulating valve (24).