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Thermistors
  Thermistors
Thermistors provide temperature feedback to the 
main board to maintain proper room temperature 
and operating conditions of the sealed system.  
On heat pump models (AZ65), thermistors also 
provide outdoor air temperature and outdoor 
coil temperature in order for the main board to 
operate the Zoneline by the most efcient means.
Thermistors: All Zoneline models have two 
indoor thermistors which are attached to the 
indoor coil.
The indoor air thermistor is mounted on the front 
of the coil to sample the incoming room air.
The indoor coil thermistor is mounted on the right 
side of the coil in a copper well to sample the coil 
temperature.
Indoor Thermistor Resistance (ohms)
All Zoneline heat-pump models have two indoor 
thermistors and two outdoor thermistors.
°F Air Coil
10 28030 28030
30 15340 15340
32 14570 14570
50 8850 8850
70 5300 5300
90 3280 3280
  Thermistors Indoor
  Thermistors Outdoor
Outdoor Thermistors Resistance (ohms) 
°F AIR COIL
10 63260 94900
30 34620 51940
32 32860 49330
50 19970 29960
70 11950 17930
90 7320 10970
One outdoor thermistor is attached to the outdoor 
coil and the other outdoor thermistor is set into 
the base assembly, enabling it to monitor outdoor 
air temperature.