Instruction Manual
D100348X012
2625 and 2625NS Volume Booster
January 2015
9
Valve Assembly Replacement
CAUTION
The distance between the exhaust port seat line on the upper valve (key 7C) and the supply port seat line on the lower valve
and stem (key 7B) is critical to ensure the deadband requirements of the volume booster. This distance must be adjusted in
accordance with the following steps before you replace the valve assembly (key 7), or the upper valve (key 7C), and lower
valve and stem (key 7B).
For key numbers refer to figure 4.
Figure 4. Volume Booster Assembly Drawing
DV4286‐B
1 . Remove the six cap screws (key 15) from the perimeter of the spring case assembly (key 3) and lift off the assembly,
taking care you do not lose the upper spring (key 8) or the spring seat (key 9).
2 . Remove the upper diaphragm (key 6), the diaphragm spacer (key 2), the diaphragm assembly (key 5), (which
includes the lower diaphragm), and the O‐rings (key 14).
3 . Unscrew the valve assembly (key 7) from the body. The seat ring (key 7A) has a 1‐1/2 inch hex for removal.
4 . Apply lubricant (key 21) to the O‐ring (key 7D), lubricant (key 23) to the lower valve and stem (key 7B), and sealant
(key 20) to the thread of the seat ring (key 7A).
5 . Install the valve assembly (key 7) into the body (key 1)—making sure the lower valve and stem (key 7B) engages
over the lower spring (key 10)—and into the bottom plug (key 4).
