Specifications

SiBE04-624 Control Specification
Function and Control 73
3.13 Automatic Defrosting
Defrost Control Start Condition
is calculated by the following formula:
= –17/256 × compressor operation frequency + 43/64 × outside air temperature – 6
However, when the calculated value is less than the lower limit indicated in the table below, the
lower limit is adopted as .
Operation during Defrosting and Termination Condition
• Operation should be conducted at 64Hz during defrosting.
• Defrosting operation must be conducted for 2 minutes, and after that, defrosting operation is
conducted until the outdoor heat exchanger temperature reaches the defrost cancellation
temperature at ºC.
• After the temperature has reached the defrost cancellation temperature, the defrosting
should be terminated.
is calculated by the following formula:
= 18 – 22/64 × outside air temperature
However, when the calculated value is outside the range between 6ºC and 22ºC, if it is less than
6ºC, 6 should be adopted and if it is more than 22ºC, 22 is adopted, as the defrost cancellation
temperature.
Outside air temperature condition Lower limit
–4ºC ≤ outdoor air temp –15ºC
–10ºC ≤ outdoor air temp. < –4ºC –20ºC
outdoor air temp. < –10ºC –22ºC
Defrost control starts
and
or
Heating mode
and
Heating mode
Compressor is in operation
6 or more minutes passed since the
compressor started its operation
The cumulative time of heating operation
reached 25 minutes or more
The cumulative time of heating operation
reached 4 hours or more
Outdoor heat exchanger temperature
< 0ºC
The state that the outdoor heat exchanger
temperature < ºC has continued for 1
minute or more