20
DEFROST CYCLES
There is no need for routine defrosting of the unit as this occurs automatically as follows:
Cycle defrost
To keep the chamber temperature stable, the refrigeration compressor is cycled on and off. During OFF
period any frost which has accumulated on the evaporator is melted by energizing a defrost heater. This
will not have any discernible effect on the chamber temperature.
Forced defrost
When the ambient humidity is high, or a large amount of damp product is being stored inside the chamber,
there is a possibility that cycle defrost may not be enough to remove all of the frost on the evaporator. In
this case, a forced defrost cycle can be initiated.
When the unit is operating under a forced defrost cycle, the current chamber temperature and dF is
displayed alternately on the digital temperature display.
Once the forced defrost cycle is completed, normal operation resumes.
CAUTION
The unit may collect excessive frost on the evaporator
if it is installed in high temperature and high
humidity location. For example, the unit starts to defrost once a week with 2
o
C setting in the ambient of
35
o
C and 80 %R.H.
The chamber temperature goes up to approximately 10
o
C temporarily during
defrosting.
REMOTE ALARM TERMINAL
The remote alarm terminal is located inside the front cover. The alarm is generated from this terminal.
Contact capacity is DC 30 V, 2 A.
between COM. and N.O.
between COM. and N.C.
At
normal
Open
Close
At
abnormal
Close
Open
Note:
The alarm is actuated when the power failure or the
power supply cord is disconnected from the outlet.
The remote alarm is silenced by pressing the buzzer
stop key (BUZZER) as the remote alarm is operated in
conjunction with the buzzer.
It is recommended to use cables with a maximum
length of 30 meters.
Connecting terminal
Summary of Contents for MPR-721 Series
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