IM-P184-09 CMGT Issue 4
9
Flow L - R
A
C
B
Fig. 3
Flow R - L
A
C
B
5.5
Before undertaking any maintenance of plant downstream of the valve both handwheels should be
isolated. Refer to Figure 3 and the Table below for the correct sequence of handwheel operation.
When handwheels A and B are closed and drain port C is opened there will be an initial discharge
as the valve depressurises. If there should be any visible discharge after a short period, consult
Spirax Sarco Service Department.
Note: Handwheels should always be opened slowly to avoid system shocks.
Operation sequence
for the Spirax SafeBloc
TM
Flow Left to Right (L-R)
Operation sequence
for the Spirax SafeBloc
TM
Right to Left (R-L)
Isolation Opening Isolation Opening
Close A Close C Close B Close C
Open C Open B Open C Open A
Close B Open A Close A Open B
For illustrative purposes refer to Steps 1 to 5 on pages 10 and 11.
Note: Name-plates are fitted to the valve to identify which handwheel operates which port. If the valve is
insulated, ensure the name-plates remain visible.
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