Compressor Preheating; External Electrical Heater Control; Electronic Expansion Valve Control - Fujitsu AOG30KATA Series Service Instruction

7-5. 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

7-6. External electrical heater control

The external electrical heater is operated as below.
Ts -3°C
Ts -12°C
When the room
temperature drops
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.)

7-7. 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
Cooling/dry mode
Heating mode
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).
7-5. Compressor preheating
Tn
Tn
Off
0°C
On
Tn: Outdoor unit heat exchanger temp.
When the room
temperature rises
Heater : Off
Heater : On
Heater : Off
- (04-28) -
2°C
Ts: Setting temperature
Ts -1°C
Ts -10°C
Pulse range
Between 47 and 480 pulses
Between 39 and 480 pulses
7. Various control