
6. To replace the lever assembly (key 16), remove
the machine screws (key 17). To replace the stem
(key 14) or access the stem seal O-ring (key 30)
also perform Body Area Maintenance procedure
steps 1 and 4 and pull the stem out of the
diaphragm casing (key 4).
7. Install the stem (key 14) into the guide insert (key 18)
and perform Body Area Maintenance procedure
steps 6 through 8 as necessary.
8. Install the lever assembly (key 16) into the stem
(key 14) and secure the lever assembly with the
machine screws (key 17).
9. Install the parts on the pusher post in the order
listed below:
• Pusher Post (key 8)
• Pusher Post Connector (key 40)
• Connector Seal O-ring (key 49)
• Diaphragm Head (key 7)
• Diaphragm (key 10), pattern side up
• Diaphragm Head (key 7)
• Hex Nut (key 21) — Tighten the hex nut 9 to
11 ft-lbs / 12 to 15 N•m to secure parts to the
pusher post connector (key 40)
• Overpressure Spring (key 39)
• Spring Holder (key 37)
• Machine Screw (key 38)
10. Insert and tighten the machine screw (key 38) with
a torque of 1 to 3 ft-lbs / 1.4 to 4.1 N•m to secure
the diaphragm parts to the pusher post (key 8).
11. Install the assembled parts in the diaphragm
casing (key 4). Make sure the lever (key 16) fits
in the pusher post (key 8) and that the holes in
the diaphragm (key 10) align with the holes in the
diaphragm casing.
12. Place the spring case (key 3) on the diaphragm
casing (key 4) so the vent assembly (key 26) is
oriented correctly and secure with the cap screws
(key 24) and hex nuts (key 23, not shown),
fingertight only.
13. Insert the control spring (key 6) into the spring
case (key 3), followed by the baffle plate (key 56)
and adjusting screw (key 35).
14. Turn the adjusting screw (key 35) clockwise until
there is enough spring (key 6) force to provide proper
slack to the diaphragm (key 10). Using a crisscross
pattern, tighten the cap screws (key 24) and hex nuts
(key 23, not shown) to 14 to 17 ft-lbs / 19 to 23 N•m
of torque. To adjust the outlet pressure to the desired
setting, refer to Startup and Adjustment section.
15. Install a replacement closing cap gasket (key 25) if
necessary and then install the closing cap (key 22).
PRX Series Maintenance
CAUTION
Always remove spring compression before
performing maintenance on this unit.
To remove spring compression, loosen
locknut (key 2, Figure 26) and back out
adjusting screw (key 1) until compression
is removed from the spring (key 7).
Lower Case Maintenance
1. Remove pressure from the pilot.
2. Remove machine screws (key 10) from lower
cover (key 21) and the separate lower cover from
the body (key 16).
3. Use a wrench to hold the stem (key 23) and
loosen the stem nut (key 20). Remove the stem
nut and washer (key 11).
4. Remove the upper diaphragm plate (key 13),
diaphragm (key 14), pad holder (key 22) and O-ring
(key 18). Inspect parts for damage or wear and
replace if necessary.
5.
Remove orifice (key 19) and O-ring (key 17).
Inspect the parts for damage or wear and replace
if necessary. Lightly lubricate the O-ring and place
in the body (key 16). Install the orifice.
6. Set the pad holder (key 22) in the body
(key 16).
7. Lightly lubricate the rims of the diaphragm
(key 14) and place it on top of the pad holder
(key 22). Set the upper diaphragm plate (key 13)
on the diaphragm.
8. Lightly lubricate the O-ring (key 18) and place
it in the lower cover (key 21).
9. Place the washer (key 11) and stem nut
(key 20) on the stem (key 23) and tighten. If also
performing Upper Case Maintenance, skip to
step 2 of the Upper Case Maintenance section.
10. Insert machine screws (key 10) in the lower cover
(key 21) and tighten uniformly to ensure proper seal.
Upper Case Maintenance
1. Remove pressure from the pilot.
2. Loosen locknut (key 2) and back out adjusting
screw (key 1) until compression is removed from
the spring (key 7). Remove cap (key 3).
3. Lift the upper spring seat (key 6), spring
(key 7) and O-ring (key 4) out of the upper cover
(key 8). Inspect O-ring and replace if necessary.
22
Type EZR