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Howard-McCray A Division of HMC Enterprises, LLC.
831 East Cayuga Street • Philadelphia, PA 19124 USA • (215) 464-6800 • (800) 344-8222
Fax (215) 969-4890 • E-Mail: [email protected] 101018
6
These freezer models utilize a non-adjustable
sealed thermostat as a defrost termination
switch. It is located in the evaporator housing on
the evaporator coil suction line.
The defrost termination control senses the
temperature inside the evaporator housing. When
the temperature, during the defrost cycle,
reaches 50
o
F it closes it's contact signalling the
defrost time clock to terminate the defrost cycle.
The differential setting of the defrost termination
control is 30
o
F, and will not open it's contact until
the temperature inside the evaporator housing
pulls down to 20
o
F. If the defrost termination
control fails to terminate the defrost cycle, the
defrost time clock will stop the defrost cycle after
the amount of time set by the fail-safe on the
defrost time clock.
Crankcase Pressure Valve
(Freezer Models)
Some freezer models utilze a crankcase pressure
valve to protect the compressor against
excessive suction pressure, during initial start-up
and upon termination of the defrost cycle. This
valve is factroy set to limit the compressor
suction pressure to 20 PSIG, and should not be
changed.
To check this setting, it is necessary that the
pressure on the inlet side, or evaporator side, of
the valve be above 20 PSIG. If not checking
during the start-up, place the cabinet into the
defrost cycle, to obtain a raised evaporator
suction pressure. With a guage installed on the
suction service valve, check for the proper
setting after the defrost cycles terminates. This
setting should be checked several times before
leaving the installation.
High Pressure Limit Control
(Freezer Models)
The cabinet is equiped with a High Pressure Limit
Control. This control is for Safety purposes, and
SHOULD NOT BE ADJUSTED UNDER ANY
CIRCUMSTANCES.
Stocking the Cabinet
After the cabinet has been started up, it should
be operated for a sufficient length of time to bring
the storage temperature down to cause the
thermostat to cycle the condensing unit. For
refrigerator models, three to four hours is usually
sufficient. For freezer models, allow at least four
to six hours is usually sufficient.
Do not load cabinet beyond shelf size limits; this
will disturb the air flow within the cabinet. Do not
allow any of the product to obstruct the fan
guards, this will have a negative effect on the
cabinet's cooling capability.
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