Bard QH242 Installation instructions manual - page 28
Manual 2100-379
Page 26
CHECKING TEMPERATURE SENSOR
1. Disconnect temperature sensor from board and
from outdoor coil.
2. Use an ohmmeter and measure the resistance of
the sensor. Also use ohmmeter to check for short
or open.
3. Check resistance reading to chart of resistance
use sensor ambient temperature. (Tolerance of
part is ± 10%.)
4. If sensor resistance reads very low, then sensor is
shorted and will not allow proper operation of the
heat pump control.
5. If sensor is out of tolerance, shorted, open, or
reads very low ohms then it should be replaced.
SOLID STATE HEAT PUMP CONTROL
TROUBLESHOOTING PROCEDURE
1. Turn on AC power supply to indoor and outdoor
units.
2. Turn thermostat blower switch to “fan on” – the
indoor blower should start. (If it doesn’t,
troubleshoot indoor unit and correct problem.)
3. Turn thermostat blower to “auto” position.
Indoor blower should stop.
4. Set system switch to “heat” or “cool”. Adjust
thermostat to call for heat or cool. The indoor
blower, compressor and outdoor fan should start.
NOTE: If there was no power to 24 volt transformer,
the compressor and outdoor fan motor will
not start for 5 minutes. This is because of the
compressor short cycle protection.
F
R
F
R
F
R
F
R
F
R
0
.
5
2
-
0
.
4
2
-
0
.
3
2
-
0
.
2
2
-
0
.
1
2
-
0
.
0
2
-
0
.
9
1
-
0
.
8
1
-
0
.
7
1
-
0
.
6
1
-
0
.
5
1
-
0
.
4
1
-
0
.
3
1
-
0
.
2
1
-
0
.
1
1
-
0
.
0
1
-
0
.
9
-
0
.
8
-
0
.
7
-
0
.
6
-
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.
5
-
0
.
4
-
0
.
3
-
0
.
2
-
0
.
1
-
0
.
0
0
.
1
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.
2
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.
3
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4
1
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5
2
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4
3
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8
4
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6
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4
3
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6
7
2
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5
4
4
6
4
4
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6
3
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4
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2
7
2
8
1
4
3
9
0
4
6
0
0
4
1
2
9
3
8
3
8
3
7
5
7
3
8
7
6
3
1
0
6
3
6
2
5
3
2
5
4
3
TABLE 6
TEMPERATURE (F) VS RESISTANCE (R) OF TEMPERATURE SENSOR