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ACCEPTANCE TESTS
Acceptance tests require continuous tests of three hours duration: 2 hours at 100% rated capacity
and 150 PSI net pump pressure; one-half hour at 70% capacity and 200 PSI; one-half hour at 50%
capacity and 250 PSI; and a spurt test at 100% capacity and 165 PSI.
Table No. 1 shows recommended set-ups and gage readings for rating tests.
To adjust nozzle pressure for the correct capacity, while maintaining the correct pump pressure, it
is necessary to make simultaneous adjustments of engine throttle and the discharge gate valve,
partially closing the latter until just the right discharge resistance is built up.
ENGINES
A fire pump imposes heavy loads on the engine that drives it, sometimes absorbing all of the power
the engine is capable of delivering at full throttle. Continuous pumping gives the engine no time to
rest. Therefore, a new engine and pump unit must be thoroughly broken-in before it is required to
deliver prolonged maximum pump performance.
We recommend a minimum break in period of 20 hours at light pumping loads, with occasional
spurt tests and interruptions. Temperature and lubrication should be checked during this period.
Engine manufacturers' power ratings usually show maximum performance of a selected, factory
adjusted engine, operating without fan, generator, muffler or other accessories, and corrected for
o
"ideal" conditions, i.e. sea level barometer (29.92" of mercury) 60
F and high humidity. Therefore,
the actual power delivered by an average truck mounted engine is considerably lower than the
manufacturers' rating, and allowances must be made in predicting pump performance.
EFFECTS OF ATMOSPHERIC CONDITIONS
ON ENGINE AND PUMP PERFORMANCE
Each one inch of drop in Barometric pressure or each 1000 feet of elevation of the pumping site
reduces engine power approximately 3 1/2% for engines not equipped with a turbo charger.
o
o
Each 12
rise in temperature above 60
F of carburetor intake air reduces engine power
approximately 1%.
Lowering of humidity reduces power slightly.
Each one inch drop in Barometric pressure or each 1000 feet of elevation reduces the maximum
possible static lift of a pump approximately one foot.
Temperature of the water supply affects the attainable suction lift of a pump. The effect is slight at
low water temperatures but becomes increasingly detrimental as the temperature rises.
o
o
A 10
rise from 70
F will subtract about 1/2 foot from the maximum attainable suction lift, while an
o
equal rise from 100
F will reduce the lift at least 1 1/2 feet.
Temperature is an important consideration when pumping from a test pit where the water is heated
by recirculation.
IF FURTHER INFORMATION IS NEEDED, CALL W.S. DARLEY & CO. AT
CHIPPEWA FALLS, WI. AT 800-634-7812 or 715-726-2650
Prepared by: EAP
Rev. #3
Approved by: MCR
Date: 1/29/07
7
Revised by: JAF
Revised Date: 5/1/13
1200509
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