IM-P186-03 CH Issue 4
10
4. Maintenance
Note: Before actioning any maintenance programme observe
the 'Safety information' in Section 1.
Warning
The bellows assembly gasket contains a thin stainless steel support ring which may
cause physical injury if not handled and disposed of carefully.
4.1 General information
Refer to Fig 4 (page 7) for view of parts.
The valve and valve seat must be kept clean.
Any strainer fitted upstream of the SRV2S and strainer screen (15) fitted inside the SRV2S
should be cleaned regularly so that the flow to the valve is not restricted.
The internal strainer is part of the valve seat assembly. This may be withdrawn by removing
the spring housing (1) and bellows assembly and unscrewing the valve assembly, using a
32 mm A / F spanner.
4.2 How to fit a new valve and seat or clean the strainer screen:
i. Release the adjustment spring pressure by turning the adjustment handwheel (2) fully
anticlockwise.
ii. Remove the spring housing by undoing the 4 spring housing bolts (7) using 13 mm A/ F spanner.
iii. Lift out the bellows assembly (5) and the gasket (6).
iv. Using a 32 mm A /F spanner, unscrew the valve seat (11) and remove the valve, the return
spring, the strainer screen, the pushrod and the guide bush.
v. Clean the strainer screen (15) or replace with a new valve and seat assembly. Note: the valve
and seat assembly incorporates the strainer screen.
vi. Reassemble in the reverse order, using new gaskets, ensuring that the components and
seating faces are clean.
vii. Tighten the valve seat (11) to the following torque 162 - 198 N m (119 - 146 lbf ft).
viii. Tighten the spring housing bolts (7) to the following torque 18 - 24 N m (13 - 18 lbf ft).
4.3 How to fit the new bellows:
Follow Steps i to iii, Section 4.2, then proceed as follows:
ix. Replace the bellows gasket and assembly, adjustment spring and the spring housing, and
tighten the spring housing bolts (7) to the following torque 18 - 24 N m (13 - 18 lbf ft).
4.4 How to fit a replacement pressure adjustment spring:
Follow Steps i and ii, Section 4.2, then proceed as follows:
x. Replace the spring (4) and bonnet assembly and tighten the spring housing bolts (7) to the
following torque 18 - 24 N m (13 - 18 lbf ft).
xi. Lift out the spring identification disc (18) and press in a new disc (if spring range has been
changed).
4.5
xii. The lower body section can be cleaned internally by removing the bottom cap (16).
xiii. Replace the 'O' ring (13) and retighten the bottom cap (16) to the required torque.
Table 1 Recommended tightening torques
or
Item No. Part N m (lbf ft)
mm
7 Hex. bolts 13 A / F M8 x 25 18 - 24 (13 - 18)
11 Valve seat 32 A / F 162 - 198 (119 - 146)
16 Bottom cap 32 A / F 115 - 125 (85 - 93)
