Gasboy XU2A - Manual (Page 14)

Operation
Page 14 MDE-4320 Gasboy UHF Pump, Blackmer® XU2A Rebuild Kit Installation Manual • June 2004
(If equipped). DO NOT operate the pump against a closed discharge valve for more than 1
minute.
Reverse Rotation
Note: 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
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 seconds 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.
Note: Some residual fluid will remain in the pump and piping.
Note: Properly dispose of all waste fluids in accordance with the appropriate codes and
regulations.
Pump Relief Valve
Note: 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.
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
The factory relief valve pressure setting is marked on a metal tag attached to the valve cover. It
is recommended that the relief valve be set at least 10 -20 psi (69 - 138 kPa) higher than the
operating pressure or the system pressure control valve setting.