Fresh Air Control; Compressor Preheating; External Electrical Heater Control - Fujitsu ASUH24LPAS Service Manual

7-6. Fresh air control

The fan motor for Fresh Air is operated in synchronization with the indoor fan operation as below.

7-7. Compressor preheating

By preheating the compressor, warm airflow is quickly discharged when the operation is started.
• Triggering condition
– 30 minutes after compressor stopped.
– Outdoor unit heat exchanger temperature (Tn)
When the jumper wire (JM2) is disconnected:

7-8. 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:
• 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.)
7-6. Fresh air control
Operation
Fan motor
(Indoor unit)
Stop
Operation
Fan motor
(for Fresh Air)
Stop
24.8°F
(-4°C)
41.0°F
(5°C)
Heater : Off
Heater : On
Heater : Off
When the room
temperature drops
Tn
Tn
Off
28.4°F
(-2°C)
On
Tn
Tn
Off
44.6°F
(7°C)
On
When the room
temperature rises
Ts -1.8°F
(Ts -1°C)
Ts -18.0°F
(Ts -10°C)
- (04-25) -
Ts: Setting temperature
7. Various control