Off Defrost Operation Control - Fujitsu ASU18RLB Service Instructions Manual

24. OFF DEFROST OPERATION 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 (7 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 24.8
compressor continuous operation more than 10 minutes, and
compressor operation integrating time lasts for more than 30 minutes.
2. OFF DEFROST END CONDITION
( Table 21 : OFF defrost release condition )
Outdoor heat exchanger temperature sensor value is higher than 60.8
Compressor operation time has passed 15 minutes.
OFF Defrost Flow Chart
Outdoor heat exchanger temperature :
Below 24.8
Compressor continuous operation :
Over 10 minutes
Compressor integrating operation :
Over 30 minutes
Outdoor heat exchanger temperature:
Over 60.8 °F( 16°C) or
Compressor ON time: Over 15 minutes
Release Condition
Heating operation stop
- 4°C)
°F(
Defrost start
Defrost Indicator:
[Operation lamp]
7 sec ON / 2 sec OFF
Defrost end
°F(
01-18
- 4°C),
°F(
16°C) or