Failed Thermistor Default Operation; Outdoor Air Thermistor (Oat) Attachment; Outdoor Coil Thermistor (Oct) Attachment - Carrier 25HNA6 Installation Instruction

Failed Thermistor Default
Operation
Factory defaults have been provided in the event of failure of
outdoor air thermistor (OAT) and/or outdoor coil thermistor
(OCT).
If the OAT sensor should fail, low ambient cooling will not be
allowed and the one-minute outdoor fan off delay will not occur.
Defrost will be initiated based on coil temperature and time.
If the OCT sensor should fail, low ambient cooling will not be
allowed. Defrost will occur at each time interval during heating
operation, but will terminate after 5 minutes.
OAT Thermistor must be locked in
place with spherical nib end facing to-
wards the front of the control box
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If there is a thermistor out of range error, defrost will occur at each
time interval during heating operation, but will terminate after 5
minutes.
Count the number of short and long flashes to determine the
appropriate flash code. Table 6 gives possible causes and actions
related to each error.
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OCT Thermistor
must be secured
tight on stub tube.
Fig. 9 - Outdoor Coil Thermistor (OCT) Attachment
Table 5 - Two-Stage Compressor Resistances
(Winding Resistance at 70 ° F_+ 20 °F / 21 ° C_+ 11 ° C)
25HNA624 25HNA636 25HNA648
2.74 1.98 1.55
0.80 0.75 0.48
Winding 25HNA660
Start (S-C) 0.74
Run (R-C) 0.36
Winding 25HNA924 25HNA936 25HNA948 25HNA960
Start (S-C) 1.40 1.29 1.52 0.60
Run (R-C) 1.32 0.89 0.64 0.49
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