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MAINTENANCE MANUAL MODELS 825Y, 825YA, 825, 825D, 825YD & 826YD
Service Procedures
Relief Valve 825, 825D and 825YD (2
1
/
2
–10") (Cont.)
the upper guide (Item 32). Remove the slip ring (Item 27a) and
inner diaphragm (item 27). Inspect, clean and replace parts as
required.
5. To reassemble, position the bead on the inner
diaphragm into the groove of the upper guide. Place the slip ring
over the diaphragm. Lubricate the retainer threads using an FDA
approved lubricant and thread the retainer onto the upper guide.
Tighten to 60 inch-lbs. of torque.
6. Insert the main stem into the diaphragm and “roll” the diaphragm
into position by grasping the end of the diaphragm and main
stem with one hand and push the upper guide towards your
other hand.
7. Test to make sure diaphragm is positioned properly by sliding the
upper guide back and forth through the full travel. It must move
freely and easily.
8. Once the inner diaphragm has been rolled, force the end of the
main stem snug against the end of the inner diaphragm. The
screw hole in the end of the main stem should be visible.
9. Replace the spring and button and tighten the screw while hold-
ing the button in place.
10. Make sure the screw (Item 48) is free of burrs that may cut the
outer diaphragm. Reposition the center label piece, that you
have saved during disassembly, over the screw head.
11. Replace the disc washer and lower guide insuring that the seat
disc is clean and in position. Lubricate the upper guide o-ring
(Item 31a) using an FDA approved lubricant, to ease installation.
DO NOT USE LUBRICANT ON ANY OTHER PART.
12. Position the relief valve module back into the body using your
finger to help guide the lower guide into the relief valve seat ring
bushing. Push the module straight in. DO NOT TWIST.
13. Replace the outer diaphragm, placing the fabric side against the
button. Work the rolled edge into the space between the mod-
ule and the body, makings sure it is not pinched or buckled.
14. Replace the cover, tighten the cover bolts, and reconnect the
sensing tubing. Return the valve to service and test to ensure
proper operation.
4a. Relief Valve Seat Ring Replacement Modular
Type Relief Valve Model 825YD
(See Figures No. 14 & 18)
1. Disconnect sensing tubing. Loosen and remove the four mount-
ing bolts (Item 38) from the adapter. Remove the relief valve.
2. Pull the seat ring (Item 36) out from the relief valve body and
inspect for damage. Replace as required.
3. Reposition the relief valve to the adapter insuring the
o-ring (Item 36b) is properly positioned. Tighten the mounting
bolts.
4. Reconnect the sensing tubing. Return to service and test the
assembly to ensure proper operation.
5a. Relief Valve Inner Diaphragm
Replacement / Modular Type Relief Valve
Model 825YD (See Figure No. 18)
1. Disconnect the sensing tubing. Remove the cover (Item 21) by
loosening and removing cover bolts (Item 25).
2. Remove the outer diaphragm (Item 26). Grasp the relief valve but-
ton (Item 24) with one hand. Insert your fingers into the rectan-
gular relief valve port on the bottom of the relief valve and apply
force to the seat disc. Pull the relief valve module straight out DO
NOT TWIST.
3. Remove the lower guide (item 35) and disc washer (item 33).
Place the relief valve module upside down on a clean flat surface.
Remove the center label piece protecting the screw head and
save this piece for reassembly. With one hand apply force suf-
ficient to hold the button against the main stem. Keep the spring
(Item 28) compressed (spring is approximately 35 lbs.) while
unscrewing the pan head screw (item 48). Remove the screw
and relieve the spring tension. Remove the button and spring.
4. Remove the main stem and un-thread the retainer (Item 34) from
