Fujitsu General AOHG45KRTA, Service Manual, Page: 113 / 154

6-5. Compressor preheating
By preheating the compressor, warm airflow is quickly discharged when the operation is started.
• Triggering condition 1
– Outdoor temperature ≤ 20°C
When outdoor temperature reaches 26°C, compressor preheating stops.
– 30 minutes after compressor stopped
• Triggering condition 2
0°C
Off
On
Tn
Tn
2°C
Tn: Outdoor unit heat exchanger temp.
6-6. External electrical heater control
The external electrical heater is operated as below.
When the room
temperature rises
When the room
temperature drops
Ts: Setting temperature
Heater : Off
Heater : On
Heater : Off
Ts -10 ° C
Ts -1 ° C
Ts -3 ° C
Ts -12 ° C
NOTES:
• When the compressor stop, external electric heater is off.
• It operates only in heating mode and when the indoor fan operates. (However, S-LOW is exclud-
ed.)
6-7. Electronic expansion valve control
The most proper opening of the electronic expansion valve is calculated and controlled under the
present operating condition based on the table below.
Operation mode Pulse range
Cooling/dry mode Between 47 and 480 pulses
Heating mode Between 39 and 480 pulses
NOTE: At the time of supplying the power to the outdoor unit, the initialization of the electronic ex-
pansion valve is operated (528 pulses are input to the closing direction).
6-5. Compressor preheating
- (04-19) -
6. Various control
CONTROL AND FUNCTIONS CONTROL AND FUNCTIONS