Fujitsu AOUH18LMAS1, Service Manual

Page: 204 / 215

 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 Condition
Heater on Heater is on as shown in following diagram of heating temperature.
Heater off
• Heater is off as shown in following diagram of heating temperature.
• Other than heating mode
• Error occurred
• Forced thermostat 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: Room temperature
Ts: Set temperature
Thon: Heater on temperature
Off
On
Tr-Ts ≥ 0.9°F
(0.5°C)
Tr-Ts
Tr-Ts (=Thon) ≤ -0.9°F
(
-0.5°C)
• Outdoor temperature zone
Combination zone
(Heat pump + Heater)
Heat pump prohibition zone
(Heater)
A: -4°F (-20°C)*
A + 3.6°F ( 2°C): -0.4°F (-18°C)
Outdoor temp.
*: Adjustable by function setting 66
2-4. Details of function
- (05-30) -
2. External input and output
FI
EL
D
W
O
R
K
IN
G
FI
EL
D
W
O
R
K
IN
G