Hale MG - Manual (Page 38)

Muscle Pumps
2-4
DO NOT PUMP ENOUGH WATER TO CAUSE A
WHIRLPOOL AT THE STRAINER. THIS
ALLOWS AIR INTO THE PUMP, RESULTING IN
ROUGH OPERATION AND PULSATION.
REPOSITION THE STRAINER OR REDUCE
FLOW TO CORRECT THE SITUATION.
As the throttle is opened, the pressure gauge
reading increases with the engine speed. If the
engine speed increases without an increase in
pressure, the pump may be cavitating.
If the pump is cavitating, warn personnel that the
pressure is being dropped. In this case, close the
throttle slowly until the pressure begins to drop,
and the engine returns to an idle. If this does not
correct the problem, here are two possibilities that
can also lead to this condition:
a. Cavitation can occur with large nozzle
tips. Solve this problem by reducing flow.
b. Cavitation can also occur when you are
pumping if air enters with the water. Even
though the pump may be primed, air leaks
can cause rough operation and an increase
of engine speed without an increase in
pressure or flow. If an air leak is
suspected, discontinue pumping and refer
to Section 4 for maintenance.
14. If a pump shutdown is desired while pumping
from draft, reduce the engine speed to idle, and
close the discharge valves. To resume pumping,
open the throttle and discharge valves. If the
pump overheats from continued churning
without water flow, open the discharge valves
periodically to release hot water.
15. Set the automatic relief valve according to
your fire department policy. If your fire
department does not have a policy to follow,
see the “TPM or Relief Valve Procedures”
later in this section.
16. If the pump overheats and is not equipped with
the Hale TRV valve, open the valve to access
the pump auxiliary cooling system, or slightly
open the tank fill line.
17. After completion of pumping procedures,
gradually reduce the engine RPM until it is at
an idle speed. Use the “Pump to Road Shift
Procedure” and “Post Operation Procedure”
provided later in this section.
Pumping From the Onboard Water Tank
1. Position the truck for convenient discharge
hose layout, and bring the truck to a complete
stop.
REFER TO THE FIRE DEPARTMENT
PROCEDURES ON SETTING WHEEL CHOCKS
AS WELL AS LAY OUT AND CONNECTION OF
SUCTION AND DISCHARGE HOSES.
2. Bring the truck to a complete stop before you
attempt to shift from road to pump.
3. Apply the truck parking brake.
4. Shift the truck transmission to the NEUTRAL
position.
5. Move the in-cab pump shift control valve from
the ROAD position to the PUMP position. The
shift warning light should come on in a second
or two, indicating a completed shift. If the
truck manufacturer has used another in-cab
valve to achieve pump shift, follow the
instructions supplied with that valve.
6. After pump shift is complete, put the truck
transmission in the proper pump operating
range or gear. For most pumpers this will be
direct drive (1:1) ratio. In addition, the
speedometer should read 5 to 15 MPH after the
shift has been completed. If the shift does not
seem to be completed, shift truck transmission
to “N” and repeat the entire procedure. Note
that some vehicles drive the speedometer from
the front wheel of the chassis. In this case, the
speedometer will not read 5 to 15 MPH after
shifting to the pump position. See the chassis
manual for details.