Pre-Heat Operation; Defrost Operation Control; Defrost Operation End Condition - Fujitsu Airstage J-II Service Manual

2-5-2 Pre-heat Operation

This pre-heat operation protects the start up failure by preventing the refrigerant from soaking into the oil in compressor.
Crankcase heater ON: 30 minutes elapsed since installed compressors stopped (However, ON when power turned on)
OFF: Compressor starts
*It doesn't control according to the temperature.

2-5-3 Defrost Operation Control

Defrost Operation Start Condition 1
Outdoor temperature <2
heating operation time
Defrost Operation Start Condition 2
Accumulated heating operation time is 40 minutes or longer
[Accumulated heating operation time is reset at the end of cooling operation or defrosting operation.]
and
an outdoor unit satisfies condition
Condition : "Heat exchange temperature
Condition : After the following all condition satisfied, "heat exchange temperature
temperature and during heat exchange liquid temperature drop" accumulated time:10minutes
(a) accumulated heating operation time
(b) 10 minutes have elapsed after outdoor unit starting
(c) 5 minutes have elapsed since oil recovery
* Defrosting start and end judgment temperature are determined by the outdoor temperature.
Defrosting start judgment temperature = 0.8 x outdoor temperature - 11.6 (However, -27.6°C to
If the calculated result is lower tha
If the calculated result is higher tha

Defrost Operation End Condition

At all outdoor units, heat exchange liquid temperature
or
when 10 minutes have elapsed from the start
(When the indoor unit connection capacity is 90% or less, after 15 minutes have elapsed.)
Defrosting end judgment temperature = 0.39 x outdoor temperature + 12.7 (However, 5 to 12°C range)
If the calculated result is lower tha
If the calculated result is higher tha
and Compressor stop count exceed 20 times at less than 10 minutes of accumulated
or below
-2°C" accumulated operating time is 180 minutes or longer
30 minutes
n -27.6 , the judgment temperature is defined as -27.6
n -6 , the judgment temperature is defined as -6
n 5 , the judgment temperature is defined as 5
n 12 , the judgment temperature is defined as 12
end judgment temperature
02-10
defrosting start judgment
- 6°C)