AERCO SWDW68 U-Tube Double-Wall Heaters w/ECS - Manual (Page 65)

HE-
111 − CORRECTIVE MAINTENANCE
Rev B Mar 2013
8-11
8.2.3 Valve Reassembly
Refer to Figure 8-1 or Figure 8-2 when performing the following procedures.
31. If the seat cage has been removed, place a NEW seat cage gasket (24) on the seating surface of the
Valve body. When this has been accomplished, use the tool described in Step 29 to replace the seat
cage (2) in the Valve body (1). Ensure that the seat cage fits tightly.
32. If they have been disassembled or are being replaced, reassemble the top piston (6) and bottom
piston (3) onto the Valve plug shaft (5) using the top piston retaining nut (46) (for 1-inch through
2-inch Valves), and the bottom piston retaining nut (50) or bottom piston retaining ring (4).
33. For 1-inch through 2-inch Control Valves, (Figure 8-1), reassemble the valve plug/seat/shaft
assembly in the following order:
a. Valve plug (5)
b. Seat retainer (34)
c. Valve seat (7)
d. Retaining disc (8)
e. Valve stem (12) and lower shaft (16)
f. Valve stem retaining nut (35)
g. Pilot spring (10)
h. Pilot spring retaining clip (3)
i. Lock washer (23)
34. For 2.5-inch, 3-inch and 4-inch Control Valves (Figure 8-2), reassemble the piston/seat/shaft
assembly in the following order:
a. Top piston (6) and bottom piston (3) assembly
b. Valve seat (7)
c. Valve stem (12) and lower shaft (16)
d. Valve seat retaining disc (8)
e. Cap screws (9)
f. Pilot spring (10)
g. Pilot spring backup washer (31), 4-inch Valve only
h. Pilot spring retainer (11)
i. Lock washer (23)
35. Holding the lower shaft (16), carefully replace the entire shaft/seat/piston assembly into the Valve body
(1) and seat cage (2).
36. Thoroughly clean the gasket surfaces of the Valve body (1) and Valve top (21) of all dirt and scale. If
necessary, use a wire brush, emery cloth or both.