26
Motor overheats thermal overload
switches
• Power supply does not match motor characteristics. Check
power supply against motor nameplate data.
• Overload caused by operating pump above its discharge
pressure. Check operating pressure against pump manu-
facturer's data plate max. rating and correct the cause of
the pressure abnormality.
Noisy operation of pump liquid end • Pump valves must move to open and close, and they will
make a clicking noise as they operate. These noises are
sometimes amplified by natural resonances in the piping
system. They are usually indications of normal valve func-
tioning.
*Noisy operating in drive casing
(pounding noise at high discharge
pressure).
• Fluid compressibility causes reversal load on gears at end
of pressure stroke. Not considered detrimental. No action
needed.
• Pump internal relief valve actuating, caused by excessive
suction lift conditions. Lower pump or raise level of liquid.
• Pump internal relief valve actuating, caused by insufficient
suction pressure. Correct poor suction condition.
• Pump internal relief valve actuating, caused by clogged or
partially blocked filter or strainer in suction line. Clean
strainer.
• Pump internal relief valve actuating, caused by clogged or
fouled suction or discharge check valves. Clean or replace.
• Pump internal relief valve actuating, caused by blocked
discharge line. Remove blockage.
• Pump internal relief valve actuating, caused by insufficient
discharge pressure. Install back pressure valve or device
to create back pressure at pump discharge connection
(see Discharge Piping, in Section II).
Improper oil level in reservoir
increases and overflows.
• Flexible diaphragm punctured by foreign material. Replace
diaphragm
Pump delivery is not adjustable. • System pressure too low. Install a back pressure valve in
the discharge line (preferred method), or install a back
pressure spring (provided) into discharge cartridge.
Pump does not develop required
pressure.
• Refer to symptom marked with an *, or check to see if sys-
tem pressure exceeds rated capacity on data plate.
• Pump internal relief valve actuating, caused by excessive
suction lift conditions. Lower pump or raise level of liquid.
• Pump internal relief valve actuating, caused by insufficient
suction pressure. Correct poor suction condition.
SECTION 5
TROUBLESHOOTING
Pump drive instruction manuals list most possible malfunctions, their causes and remedies. The follow-
ing problems are peculiar to Model XT and Model XW Pumps and may be repaired as indicated below.
SYMPTOMS REMEDIES
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