Hale Trailer - Manual (Page 40)

❑ Operation
40 Operation - Skid & Trailer
p/n: 029-0810-00-0
❑ Air enters with the water - Air leaks can cause rough operation and an
increase in engine speed without an increase in pressure or flow.
If an air leak is suspected, discontinue pumping - see heading “Trouble-
shooting” on page 47.
❑ Hot water - see Figure F-2: “Lift Loss from Temperature” on page 67.
❑ Low barometer - see Figure F-3a: “Lift Loss from Barometric Reading”
on page 67.
❑ High lift - see Figure F-3: “Lift Loss from Elevation” on page 67.
Note: Also see Section “Appendix F: Cavitation” on page 65.
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.
16. To avoid pump overheating, if not equipped with the Hale TRV valve, open
the pump auxiliary cooling system valve, or slightly open a discharge valve.
17. After completion of pumping procedures, gradually reduce the engine RPM
to IDLE speed and close discharge valves. Also see heading “Post Opera-
tion Procedures” on page 42.
Draft Operation Limiting Factors
The effect of raised water temperatures when pumping from a positive pressure
source (i.e., a hydrant) is negligible on fire pump performance. However, when
pumping from draft (static source such as a pond, lake or basin), elevated water
temperature does have a limiting effect.
Water temperatures above 95°F (35°C) cause a noticeable decrease in lift
when drafting. Also see Figure F-2: “Lift Loss from Temperature” on page 67.
Barometric pressures below 29” Hg. can also limit lift when drafting. High ele-
vations and storm conditions can affect maximum flow available from any pump.
Also see Figure F-3a: “Lift Loss from Barometric Reading” on page 67.