Hale MG - Manual (Page 61)

Muscle Pumps
4-3
CONDITION POSSIBLE CAUSE SUGGESTED CORRECTION
PUMP LOSES PRIME
OR IT WILL NOT
PRIME (CONTINUED)
Air Trap in Suction Line
Pump Pressure too low when
nozzle is opened
Air Leaks Avoid placing any part of the suction hose
higher than the suction intake. Suction hose
should be laid with continuous decline to
water supply. 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 discharge valve
slowly.
Attempt to locate and correct air leaks using
the following procedure.
1. Perform dry vacuum test on pump per
NFPA standards with 22 inches minimum
vacuum required with loss not to exceed
10 inches of vacuum in 5 minutes.
2. If a minimum of 22 inches of vacuum
cannot be achieved, the priming device or
system may be defective, or the leak is
too big for the primer to overcome (such
as an open valve). The loss of vacuum
indicates leakage and could prevent
priming or cause loss of prime.
3. Attempt above dry prime and shut off
engine. Audible detection of a leak is
often possible.
4. Connect the suction hose from the hydrant
or the discharge of another pumper to
pressurize the pump with water, and look
for visible leakage and correct. A pressure
of 100 PSI (6.9 BAR) should be
sufficient. Do not exceed pressure
limitations of pump, pump accessories, or
piping connections.
5. Check pump packing during attempt to
locate leakage. If leakage is in excess of
recommendations, adjust accordingly
following instructions in Section 3.
6. The suction side relief valve can leak. Plug
the valve outlet connection and retest.