External Electrical Heater Control; Electronic Expansion Valve Control; Prevention To Restart For 3 Minutes (3 Minutes St); 4-Way Valve Control - Fujitsu ASUH18LMAS Service Manual

7-9. External electrical heater control

The external electrical heater is operated as below.
Ts -5.4°F
(Ts -3°C)
Ts -21.6°F
(Ts -12°C)
NOTES:
• →hen the compressor stop, external electric heater is off.
• It operates only in heating mode and when the indoor fan operates. (However, S-LO→ is exclud-
ed.)

7-10. 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).

7-11. Prevention to restart for 3 minutes (3 minutes st)

→hen the compressor fails to start for the number of times below, it does not enter operation status
for 3 minutes.
Retry number
Retry set number
→hen the compressor fails to start in the retry set number above, the compressor is stopped.

7-12. 4-way valve control

• If heating mode is selected at the compressor start, 4-way valve is energized for heating.
• →hen the air conditioner is switched between cooling and heating mode, compressor is stopped,
and the 4-way valve is switched when the 3 minutes passes and the compressor is started.
7-9. External electrical heater control
Heater : Off
Heater : On
Heater : Off
When the room
temperature drops
When the room
temperature rises
Ts -1.8°F
(Ts -1°C)
Ts -18.0°F
(Ts -10°C)
Between 47 and 480 pulses
Between 39 and 480 pulses
- (04-26) -
Ts: Setting temperature
Pulse range
30
3
7. Various control