Owner's manual

18 Manual p/n: 029-0020-79-0
4DK Series Pumps
SUGGESTED CORRECTIVE ACTIONCONDITION POSSIBLE
CAUSE
PUMP LOSES
PRIME OR WILL
NOT PRIME -
continued
Air trapped in
suction line -
continued
Pump pressure too
low when nozzle is
opened
Air leaks
● If trap in hose is unavoidable, repeated priming may be
necessary to eliminate air pocket in suction hose.
● Prime the pump again and maintain higher pump pressure
while opening the discharge valve slowly.
● Attempt to locate and correct air leaks.
● The suction side relief valve can leak. Plug the valve outlet
connection and retest.
INSUFFICIENT
PUMP
CAPACITY
Insufficient engine
power
Relief valve improp-
erly set - if so
equipped
Engine governor set
incorrectly - if so
equipped
Truck transmission
is in wrong gear, or
clutch is slipping
Air leaks
● Engine power check or tune up may be required for peak
engine and pump performance.
● If the relief valve pressure is set too low it allows the valve to
open and bypass fluid.
● Reset the relief valve pressure accordingly.
● If the engine governor is set too low when on automatic, the
engine speed decelerates before the desired pressure is
reached.
● Reset the governor per manufacturer's procedures.
● Recheck the pumping procedures for the recommended
transmission or gear range. See truck manual for assistance.
● Use mechanical speed counter on the pump panel to check
speed against possible clutch or transmission slipping or
inaccurate tachometer. (Check the truck manual for possible
speed counter ratio.)
● See Possible Causes "Air leaks" under PUMP LOSES PRIME
OR WILL NOT PRIME, beginning on page 17.
INSUFFICIENT
PRESSURE
● See previous section: Insufficient Pump Capacity.
ENGINE SPEEDS
TOO HIGH FOR
REQUIRED
CAPACITY OR
PRESSURE
Chart continued on
next page
Truck transmission
in wrong range or
gear
● Check recommended procedures for correct transmission
selection. (See truck manual for assistance.)