11/19
NT 1003-A00 09 18 AZ O e
6. BYPASS
6.1 Operation
The bypass operates like a safety valve, by automatically
limiting the discharge pressure at the value for which it
is adjusted.
When the discharge pressure reaches the adjusted
pressure of the spring, the valve
803
opens, thus permit-
ting the partial or total return of the liquid to the inlet side
of the pump.
It should be noted that the role of the bypass, as a safety
device, is limited to protecting the pump against acci-
dental over-pressure. For all electric motors, unless the
model used can handle the increased load due to maxi-
mum overpressure, it is vital to provide appropriate over-
load protection.
6.2 Orientation
The bypass only protects the pump in one direction of
operation. Consequently it is necessary to check that the
pumps direction of operation is correct by verifying that
the cap
810
is located on the inlet side. The bypass must
be reversed if in the wrong direction.
WARNING
FAILURE TO RELIEVE SYSTEM
PRESSURE PRIOR TO PERFORMING
PUMP SERVICE OR MAINTENANCE
CAN CAUSE PERSONAL INJURY OR
PROPERTY DAMAGE.
Hazardous pressure
can cause
personal injury
or property damage.
WARNING
IF PUMPING HAZARDOUS OR TOXIC
FLUIDS, THE SYSTEM MUST BE FLUS-
HED PRIOR TO PERFORMING ANY
SERVICE OPERATION.
Hazardous or toxic
fluids can cause
serious injury.
CAUTION
THE PUMP LUBRICANT IS VERY SLIPPE-
RY AND MAY CAUSE SERIOUS INJURY.
ANY SPILLS MUST BE CLEANED UP.
Slippery lubricant.
Spills should be
cleaned up.
WARNING
INCORRECT SETTINGS OF THE
PRESSURE RELIEF VALVE CAN CAUSE
PUMP COMPONENT FAILURE, PERSO-
NAL INJURY AND PROPERTY DAMAGE.
Hazardous pressure
can cause
personal injury
or property damage.
