MIL-PRF-12574M
c. In 4.3.2.3.2 (g) 2, temperature of the air entering the
evaporator has been maintained at 35 0F + 10F in place of 0 0F
temperature specified.
4.3.2.4 Defrost test . With the refrigeration unit operating in a
maximum ambient temperature of 20 0F and the insulated structure
maintained at 0 0F + 10 0F, the evaporator shall be frosted up by
spraying water on the coil surface or evaporating water in the box.
After the coil is frosted, the refrigeration unit shall be set on
the defrost cycle and the condensate collected and weighed.
Verification shall be made that the unit operates through a complete
defrost cycle, that no less than 6 pounds of condensate is produced
in 30 minutes, that no overloading of the compressor motor or diesel
engine occurs, that there is no damage to the compressor because of
lack of lubrication or refrigerant "slugging" and that no
condensate gets into the food storage area when the refrigeration
cycle begins again. Verify that there is no ice on the coil at the
end of the defrost cycle.
4.3.2.5 Control panel inspection . During the 4-hour operation
test, verification shall be made that the on/off switch and
operation indicator works properly; the refrigeration temperature
control and internal refrigerator temperature indicator agree;
pressure reading indicators agree with pressures being recorded, and
the operation running time indicator agrees with the test timing
device. For type I units the fuel capacity and voltage indicators
shall be visually checked for proper operation. Functioning of the
defrost operation indicator shall be visually verified during the
defrost test.
4.3.2.6 Ozone-depleting chemicals inspection . Visually check
publication SD-14 (see 6.6) to verify that the refrigerant used in
the refrigeration unit is not listed.
4.3.2.7 Temperature control inspection . Visually inspect the
o
temperature control to verify that temperatures from minus 10
F to
0
0
plus 50 F can be selected in increments not less than 2
F and not
greater than 6 0F.
4.3.2.8 Diesel engine operation demonstration . During the 72-
hour operation test on type I refrigeration units, observe that
diesel fuel is used for one 36-hour period of operation and JP-8
fuel is used for the other 36-hour period of operation.
4.3.2.9 Power requirements demonstration . During the 72-hour
operation test on type II refrigeration units, observe that the unit
operates on a 208/230 volt, 3-phase, 60-Hz power
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