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Thermistor curve, Thermistor sensor comparison, Failed thermistor default operation – Bryant Evolutiont Series s with Puronr Refrigerant 286A User Manual

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13

0

10

20

30

40

50

60

70

80

90

0

(-17.77)

20

(-6.67)

40

(4.44)

60

(15.56)

80

(26.67)

100

(37.78)

120

(48.89)

TEMPERATURE °F (°C)

RESISTANCE (KOHMS)

THERMISTOR CURVE

A08054

Fig. 7 -- Resistance Values Versus Temperature

If the outdoor air or coil thermistor should fail, the control will

flash the appropriate fault code. (See Table 6.)
IMPORTANT: The outdoor air thermistor and coil thermistor
should be factory mounted in the final locations. Check to ensure
thermistors are mounted properly per Fig. 8 and Fig. 9.

Thermistor Sensor Comparison

The control continuously monitors and compares the outdoor air

temperature sensor and outdoor coil temperature sensor to ensure
proper operating conditions. The comparison is:

S

In cooling if the outdoor air sensor indicates ≥ 10_F

(≥ 5.6_C) warmer than the coil sensor (or) the outdoor air

sensor indicates ≥ 20_F (≥ 11_C) cooler than the coil sensor,

the sensors are out of range.

S

In heating if the outdoor air sensor indicates ≥ 35_F (≥

19.4_C) warmer than the coil sensor (or) the outdoor air

sensor indicates ≥ 10_F (≥ 5.6_C) cooler than the coil sensor,

the sensors are out of range.

If the sensors are out of range, the control will flash the appropriate
fault code as shown in Table 6.
The thermistor comparison is not performed during low ambient
cooling or defrost operation.

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.
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.

OAT Thermistor must be locked in

place with spherical nib end facing to-

wards the front of the control box

Fig. 8 -- Outdoor Air Thermistor (OAT) Attachment

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)

Winding

286A024

286A036

286A048

286A060

Start (S--C)

2.74

1.98

1.55

0.74

Run (R--C)

0.80

0.75

0.48

0.36

Winding

288A024

288A036

288A048

288A060

Start (S--C)

1.40

1.29

1.52

0.60

Run (R--C)

1.32

0.89

0.64

0.49

286A

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