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RUNNING THE PUMP IN REVERSE ROTATION
NOTICE:
Pump should be operated in reverse rotation for no more
than 10 minutes and only when a separate pressure relief
valve is installed to protect the pump from excessive
pressure.
It may be desirable to run the pump in reverse rotation for
system maintenance. The pump will operate satisfactorily in
reverse rotation for a LIMITED time,
at a reduced
performance level.
FLUSHING THE PUMP
NOTICE:
If flushing fluid is to be left in the pump for an extended
time, it must be a lubricating, non-corrosive fluid. If a
corrosive or non-lubricating fluid is used, it must be
flushed from the pump immediately.
1. To flush the pump, run the pump with the discharge
valve open and the intake valve closed. Bleed air into
the pump through the intake gauge plug hole or through
a larger auxiliary fitting in the intake piping. Pump air for
30 second intervals to clean out most of the pumpage.
2. Run a system compatible flushing fluid through the pump
for one minute to clear out the remainder of the original
pumpage.
3. To remove the flushing fluid, follow step 1 above.
NOTICE:
After flushing the pump some residual fluid will remain in
the pump and piping.
NOTICE:
Properly dispose of all waste fluids in accordance with
the appropriate codes and regulations.
PUMP RELIEF VALVE
NOTICE:
The pump internal relief valve is designed to protect the
pump from excessive pressure and must not be used as
a system pressure control valve.
GNX(H) series pumps are fitted with an internal pressure
relief valve that bypasses back to the suction side of the
pump.
Pumping volatile liquids under suction lift may cause
cavitation. Partial closing of the discharge valve WILL result
in internal relief valve chatter and is NOT recommended. For
these applications, install an external system pressure
control valve, and any necessary bypass piping, back to the
storage tank.
A system pressure control valve is also recommended when
operating for extended periods (more than 1 minute) against
a closed discharge valve.
RELIEF VALVE SETTING AND
ADJUSTMENT
The relief valve pressure setting is marked on a metal tag
attached to the valve cover. Generally, the relief valve should
be set at least 15 - 20 psi (1.0 - 1.4 Bar) higher than the
operating pressure, or the external bypass valve setting (if
equipped).
Incorrect settings of the pressure relief
valve can cause pump component
failure, personal injury, and property
damage.
Hazardous pressure
can cause personal
injury or property
damage
Relief valve cap is exposed to pumpage
and will contain some fluid
Hazardous or toxic
fluids can cause
serious injury.
DO NOT remove the R /V Cap OR adjust the relief valve
pressure setting while the pump is in operation.
1.
To INCREASE the pressure setting,
remove the relief
valve cap (1) and gasket (88). Loosen the locknut(3), if
equipped. Turn the adjusting screw (2)
inwar
d, or
clockwise. Inspect the R/V cap gasket (88) and replace
as required. Reattach the R/V cap gasket and cap.
2.
To DECREASE the pressure settin
g, remove the relief
valve cap (1) and gasket (88). Loosen the locknut(3), if
equipped. Turn the adjusting screw (2) out
war
d, or
counterclockwise. Inspect the R/V cap gasket (88) and
replace as required. Reattach the R/V cap gasket and
cap.
Refer to the individual Blackmer pump parts lists for various
spring pressure ranges. Unless specified otherwise, pumps
are supplied from the factory with the relief valve adjusted to
the mid-point of the spring range.
