2” NPT MULTI-PORT RELIEF VALVE MANIFOLD – SERIES
Form #996 Multi-Port Relief Valve Manifold IOM Rev B 11/05/15
NOTE
It is not necessary or desirable to lower tank vapor pressure
when removing or installing a relief valve. Vapor pressure
provides additional closing force to manifold port valve.
TO REMOVE A SAFETY RELIEF VALVE:
1.
Slowly turn valve selection handle until ID number of relief
valve to be replaced is aligned with the “Port Closed”
indicator on the manifold body.
2.
Vent trapped vapor by opening the vent valve located
below the relief valve to be removed.
Note: It may be necessary to make slight adjustments to
the position of the valve port selection handle to
completely seal the internal pilot valve. If venting
continues, close vent valve and unseat manifold valve by
slowly moving valve port selection handle a quarter turn or
more in either direction then return handle to close desired
port.
3.
If pipe-aways are installed, see section of pipe-away
removal.
4.
WARNNG: Wait for venting to stop before remove valve.
After venting stops, remove relief valve.
5.
Remove cap and valve stabilizing clamp from relief valve.
6.
Remove/Install relief valve from manifold using MEC
MEP123 installation tool.
7.
Close vent valve and cover open port with weather cap
attached to manifold gear boot.
Note: Relief valve must be replaced within a short period as
the manifold port valve is not intended for primary seal for
extended periods of time.
TO INSTALL A SAFETY RELIEF VALVE:
1.
Remove weather cap from closed manifold port.
2.
Install MEC relief valve of proper size and rating according
to instructions provided with the valve. WARNING: Valve
must be installed with weep hole oriented away from
operator, from all other valves, manifolds, and other
pressure containing piping and systems, see figure 1.
3.
Reinstall valve stabilizing bracket and tighten securely.
4.
If installing pipe-aways, see section of pipe-away
installation.
5.
Rotate the valve selection handle to a position between
two port numbers to ensure all reliefs are active.
6.
Check connection joints for leaks using “Marshall Excelsior”
Leak Detector solution.
7.
Install cap onto relief valve outlet.
PIPEAWAYS
Pipe-aways may be required by local codes, laws and
regulations depending on the installation. The addition of
pipe-away adapters and piping will restrict the flow. To
properly protect any container, the total system flow must be
sufficient to relieve pressure at the pressure setting of the
relief valve in accordance with all applicable codes.
For installing or removing valves, see installation form
for Pipe-away Kit.
If installing pipe-aways, use Marshall Excelsior pipe-away kit,
MEP178K.
