MIL-PRF-12574M
that the type II unit weighs no more than 775 pounds.
4.3.3.2 Transportability test . The refrigeration unit loaded to
1 1/2 times the weight of the unit, shall be lifted, transported,
and placed in position by a forklift truck without securing the unit
in any way to the truck. During the transport, the truck will be
driven over a 4-inch by 4-inch board so either the two left or two
right tires go over the board. Upon completion, visually examine
the refrigeration unit to verify that there is no damage or
distortion.
4.3.3.3 Design reliability test .
A 2500-hour design reliability
test shall be run as follows:
a. A maximum of two units shall be used for this test. When two
units are used, each unit shall be tested for a minimum of 1000
operating hours and their combined testing time must equal 2500
operating hours.
Operating hours for the units shall be the hours
the compressor is operating.
b. The refrigeration unit shall be clamped to the evaporator
opening of the calorimeter (see 4.3.2.3.1) with a minimum volume of
150 cubic feet.
c. A combined heat load of approximately 4000 Btu/hr shall be
imposed on the unit so the compressor will cycle with running time
of approximately 75 percent when the condenser air entering
temperature is 110 0F.
d. The air entering the condenser and surrounding the condensing
0
section shall be maintained at a minimum of 110
F for 90 percent of
0
the operating hours, and at a minimum of 125
F for 10 percent of the
operating hours.
e. The defrost control shall be set for two defrosts in a 24-
hour period of operating time.
f. The refrigeration unit shall be operated with the thermostat
set at 0 0 F for 36 hours and at 40 0 F for the next 36 hours. This
cycle shall be repeated until all operating hours have been
completed. During the test, suction and discharge pressures, air
temperature entering the condenser, refrigerated enclosure
temperature, and compressor operating hours shall be recorded every
hour on automated recording instruments.
g. Failure of the unit to maintain the temperature of the
enclosure, failure to start and operate, failure to defrost, or any
16
For Parts Inquires call Parts Hangar, Inc (727) 493-0744
© Copyright 2015 Integrated Publishing, Inc.
A Service Disabled Veteran Owned Small Business