Fujitsu AUUH18LUAS Service Manual page 219

 Auxiliary heat pump control
• External heater output
Operation
Heater on
Heater off
– Temperature of heater on (Thon): Set temperature (Ts) -0.9°F (-0.5°C)
– Temperature of heater off: Set temperature (Ts) +0.9°F (+0.5°C)
Tr-Ts ≥ 0.9°F
(0.5°C)
• Auxiliary heat pump On/Off
– Temperature of heat pump on (Thon): Adjustable by function number 62 (Operating temperature
switching of heat pump).
– All control temperatures will shift by adjusting "Thon".
Tr-Ts ≥ 0.9°F
(0.5°C)
*: →hen room temperature stays in this zone for a specific time, auxiliary heater is turned on. For
details, refer to function number 71.
3-5. Details of control output 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 (-0.5°C)
On
Tr-Ts
Off
*
Tr-Ts (=Thon) < -0.9°F (-0.5°C)
On
- (05-37) -
Condition
Tr: Room temperature
Ts: Set temperature
Thon: Heater on temperature
Tr: Room temperature
Ts: Set temperature
Thon: Heat pump on temperature
3. External input and output (for indoor unit)