Cashco 8900 - Manual (Page 9)

9 IOM-8900 Series
4. Rotate lower jam nuts (36) CCW two -
three revolutions to loosen from weather hood.
Rotate weight studs CCW and remove from top of
weatherhood.
4. Proceed to Step D. or E.
D. Vacuum Seat Ring Replacement:
- For ERV without Flame Screen:
1. Position the pressure pallet assembly (3)
with vacuum seat ring (8) face down - use 4” x 4”
blocks as support. DO NOT ALLOW DIAPHRAGM
(2) OR RETAINER RING (4) TO REST ON THE
BLOCKS.
2. Rotate cap screws (36) CCW to remove
weather hood (11). Remove screen (6). Around
the bolt circle of the weather collar (7) place match
“marks” to indicate the location of each weather
hood support (10).
3. Rotate each support (10) CCW and remove.
Rotate seat ring nuts (73) CCW to remove nuts,
lockwashers (74), weather collar (7) and gasket (5).
4. Re-Orient the pressure pallet assembly
(3) with the seat ring (8) face up, again resting on
the blocks. Rotate cap screw (9) CCW and remove
seat ring (8) and seat ring gasket (5).
6. Clean sealing surfaces on seat ring (8) and
both sides of pressure pallet (3).
7. Install new seat ring gasket (5). Position
seat ring (8) on gasket (5), align holes and thread
cap screws (9) into pallet using a star pattern and
tighten to 15 ft. lbs.
8. Re-Orient the pressure pallet assembly (3)
with the seat ring (8) face down, again resting on the
blocks. Position new gasket (5) and weather collar
(7) over cap screws (9).
9. Using the “marks” per 2. previous, install the
weather hood supports (10) on the weather collar
and tighten to 15 ft-lbs.. On remaining cap screws,
install lock washers (74), nuts (73) and tighten to 15
ft-lbs.
10. Reposition the screen (6) around the
weather hood supports (10). Align holes in weather
hood (11) with holes in supports (10) and install
studs/jam nuts or cap screws (36), torque to 15 ft-
lbs. Install lower canister (13) into weather hood
(11).
11. From underside of pressure pallet (3)
assembly slide vacuum pallet (18) assembly -
threaded end of stem (21) fi rst, up through center
hole of lower canister (13).
12. Into the open end of the canister, install
lower spring button (14) and spring (16) over stem
(21) into the lower canister (13). Make sure that
lower spring coil rests inside the retainer groove of
the lower spring button (14).
13. Place upper spring button (14) on top of
vacuum spring (16). Make sure that top spring coil
rests inside the groove of the spring button.
14. Place one hand on the upper spring button
(14) and compress the spring (16) until the threads
of pallet stem (21) protrude thru upper spring button
(14). With other hand, thread one jam nut (25) on to
pallet stem (21).
NOTE: Check to ensure that as the pallet assembly
(18) is lifted upwards that the vacuum seat ring (8)
is centered and aligned with vacuum pallet (18)
assembly.
15. Continue to rotate jam nut (25) CW until
the height from the top of the pallet stem (21) to the
top of the upper spring button (14) is equal to the
value recorded per A.1. previous.
16. Thread a second jam nut (25) on pallet
stem (21). Secure tight against fi rst jam nut (25).
17. Place upper spring canister (15) over
vacuum spring (16), align bolt holes in canister
fl anges.
18. Insert cap screws (28) into fl ange bolt
holes and tighten snug - torque to 10 ft-lbs. NOTE:
DO NOT over tighten screws.
Proceed to F. or G.
E. Vacuum Seat Ring Replacement:
- For ERV with Flame Screen:
NOTE: Installation of the pressure pallet diaphragms
should be completed prior to installation of the
vacuum seat ring.
WARNING
SPRING UNDER COMPRESSION. Exercise cau-
tion to avoid accidental spring release. Vacuum
spring (16) is now under compression and the ac-
cidental release of force may result in fl ying parts
that could cause personal injury.