Fujitsu AU G18LVLB Series Service Instruction page 24

3. Defrost Flow Chart
The defrosting shall proceed by the integrating operation time, outdoor temperature
and outdoor heat exchanger temperature as follows.
1st defrost
Compressor
Compressor
integrating integrating
operation: operation:
Over 22 min. Over 62 min.
Outdoor Outdoor
heat exchanger heat exchanger
temperature: temperature:
Below - 9°C
Below - 5°C
Heating operation start : Compressor ON
2nd and later defrost
Compressor
integrating
operation:
Over 40 min.
Tn-Tn10 < - 5deg
Tn-Tnb < - 2deg
However, Tn <- 6°C
=
Defrost start
Defrost Indicator:
[Operation lamp]
6 sec ON / 2 sec OFF
Outdoor heat exchanger temperature:
Over +13°C
or
Compressor ON time: Maximum 15 minutes
Defrost end
01-21
(Not defrosted for 10 minutes)
Integrating defrost
(Constant monitoring)
Compressor
OFF count :
40 times
(Less than 10min.)
Compressor OFF
Outdoor fan motor OFF
30 sec later four - way valve OFF
35 sec later compressor ON
Outdoor fan motor ON
( - 6°C< OT < 1°C )
= =
OT :Outdoor Temperture
Compressor
integrating
operation:
Over 240 min.
Outdoor
heat exchanger
temperature:
Below - 3°C