Groth 3000 Series - Manual (Page 15)

12
clear the piston without scratching the piston or
permanently deforming the rings.
Secure the body in a vise with the bottom surface
facing upward and the inlet port accessible (See
Figure 12). Spray the piston sub-assembly with an
anti-galling lubricant and insert it and the guide ring
[23], into the body. Install the body O-Ring [22].
Set the piston diaphragm into the upper actuator
housing with reinforcing fabric away from the piston
(opposite to the supply pressure). Refer to Figure 12.
Attach the upper diaphragm case [12] to the body,
being sure that the piston wrench flats are accessible
through the inlet port before tightening the
countersunk screws [30].
Figure 12: Piston/Body/Diaphragm
21
31
32
33
34
26
13
38 37
19
21
23
24
25
22
WRENCH
FLATS
Attach the sense diaphragm [14], support plate [13],
back-up plate [19] and washer [38] (See Figure 15).
Clean thread surfaces thoroughly and apply Loctite
Threadlocker No. 222 to countersunk screw [37].
Align diaphragm and case holes and hold piston with
a 3/8" wrench through inlet port while tightening the
countersunk screw [37].
Attach the gasket [39] and lower diaphragm case [15]
with hex bolts, lockwashers and nuts [16, 17, & 18].
Clean all surfaces before assembly and tighten bolts
uniformly; refer to Table 8 for recommended torque.
Reposition the assembly in the vise. Install the upper
piston diaphragm [21], retainer [9] and pin [8]. Hold
piston with 3/8" wrench through inlet port while
tightening pin. Install the bonnet adapter ring [10],
spring [6], spring buttons [5] and spring bonnet [4].
Attach bonnet to body with hex bolts [28] and
lockwashers [29]. Tighten bolts uniformly; refer to
Table 8 for recommended torque.
Figure 13: Spring Bonnet Assembly
1
2
3
5
4
6
28
7
29
Thread set pressure adjusting screw [2] into bonnet
until it engages the upper spring button. Tighten lock
nut [3] and replace cap [1].
Note: See Recommended Testing and Setting
Procedure.
TABLE 8
RECOMMENDED BOLT TORQUE
[FT. - LB.]
Screw Size
1/4" 5/16" 3/8" 7/16" 1/2"
Torque
6 11 20 32 44
WARNING
Replace bonnet vent [7] or case vent [11] if
damaged or restricted. A plugged case vent could
prevent the regulator from closing. This could
cause an over-pressure condition in the tank. A
plugged bonnet vent would prevent the release of
supply pressure from the bonnet. This could cause
personal injury when disassembling.