Fujitsu ASUG09LZAS Design & Technical Manual page 40

 Auxiliary heater 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 number 62 (Operating temperature
switching of external heaters).
• All control temperatures will shift by adjusting "Thon".
• Outdoor temperature zone boundary A: Adjustable by function setting number 66.
• External heater output
Tr-Ts ≥ 0.9°F
(0.5°C)
• Outdoor temperature zone
A + 3.6°F ( 2°C): -0.4°F (-18°C)
*: Adjustable by function setting 66
9-4. 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.
Combination zone
( Heat pump + Heater)
A: -4°F (-20°C)*
Heat pump prohibition zone
Condition
Tr: Room temperature
Ts: Set temperature
(-0.5°C)
Thon: Heater on temperature
(Heater)
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9. External input and output