Fujitsu AOU42RGLX Design & Technical Manual page 65

 Heater selection control by outdoor temperature 2
This control selects heat pump or external heater according to the outdoor temperature. Even when
outdoor temperature is high, the heating is performed by using both of heat pump and external
heater.
Operation
Heater on
Heater off
• Temperature of heater on (Thon): Adjustable by function setting no. 62 (Operating temperature
switching of external heaters).
• All control temperatures will shift by adjusting "Thon".
• Outdoor temperature zone boundary A: Adjustable by function setting no. 66 for outdoor unit.
• External heater output
Tr-Ts ≥ 0.9°F
(0.5°C)
• Outdoor temperature zone
• Operation status
Outdoor temperature
Outdoor temperature zone *
* The outdoor temperature zone transition from one to another will stay in that zone for minimum of 30 min.
NOTE: In following operations, compressor will be on in heat pump prohibition zone.
• Other than heating
• Test run
8-4. Details of function
Heater is on as shown in following diagram of heating temperature.
• Heater is off as shown in following diagram of heating temperature.
• Other than heating mode
• Error occurred
• Forced thermostat off
Tr-Ts
Off
Tr-Ts (=Thon) ≤ -0.9°F
On
Outdoor temp.
A + 3.6°F ( 2°C): -0.4°F (-18°C)
*A: -4°F (-20°C)
46.4°F (8°C)
42.8°F (6°C)
(Factory setting)
-0.4°F (-18°C)
-4°F (-20°C)
On
Comp. On/Off
Off
12 V
Heater
0 V
On
Fan
Off
Condition
Tr: Room temperature
Ts: Set temperature
(-0.5°C)
Thon: Heater on temperature
Combination zone
(Heat pump + Heater)
Heat pump prohibition zone
(Heater)
*Adjustable by function setting no. 66.
Heat pump
prohibition
zone
- 59 -
Combination zone
8. External input and output