Off Defrost Opeartion Control; Off Defrost Operation Condition; Off Defrost End Condition - Fujitsu ASTG18KMTC Service Instruction

24. OFF DEFROST OPEARTION CONTROL

When operation stops in the [Heating operation] mode, if frost is adhered to the outdoor unit heat
exchanger, the defrost operation will proceed automatically. In this time, if indoor unit operation
lamp flashes slowly (6 sec ON / 2 sec OFF), the outdoor unit will allow the heat exchanger to defrost,
and then stop.

1. OFF DEFROST OPERATION CONDITION

In heating operation, the outdoor heat exchanger temperature is less than - 4°C,
compressor continuous operation more than 10 minutes, and
compressor operation integrating time lasts for more than 30 minutes.

2. OFF DEFROST END CONDITION

Outdoor heat exchanger temperature sensor value is higher than 16°C
or Compressor operation time has passed 15 minutes.
OFF Defrost Flow Chart
Outdoor heat exchanger temperature:
Below - 4°C
Compressor continuous operation:
Over 10 minutes
Compressor integrating operation:
Over 30 minutes
Outdoor heat exchanger temperature:
Over 16°C or
Compressor ON time: Over 15 minutes
Release Condition
Heating operation stop
Defrost start
Defrost Indicater:
[Operation lamp]
6 sec ON / 2 sec OFF
and
[Defrost lamp]
Lighting
Defrost end
01-17