Bard QH602 Heat Pump User Manual


 
Manual 2100-420H
Page 29 of 34
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. NOTE: A thorough understanding of the defrost
cycle sequence is essential. Review that section
earlier in this manual prior to troubleshooting the
control. Turn on AC power supply to unit.
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. NOTE: Many models have a
1-minute blower time delay on “off” command;
wait for this to time-out.
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.
TABLE 6
TEMPERATURE (F) VS RESISTANCE (R) OF TEMPERATURE SENSOR
FR FR FR FR
0.52-
0.42-
0.32-
0.22-
0.12-
0.02-
0.91-
0.81-
0.71-
0.61-
0.51-
0.41-
0.31-
0.21-
0.11-
0.01-
0.9-
0.8-
0.7-
0.6-
0.5-
0.4-
0.3-
0.2-
0.1-
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
0.01
0.11
0.21
178691
990091
585381
813771
982171
784561
409951
925451
553941
473441
675931
659431
605031
912621
980221
801811
272411
575011
010701
475301
062001
46079
18939
80019
93188
17358
99628
12108
23677
03257
01927
07607
70586
81466
99346
94426
56506
54785
0.31
0.41
0.51
0.61
0.71
0.81
0.91
0.02
0.12
0.22
0.32
0.42
0.52
0.62
0.72
0.82
0.92
0.03
0.13
0.23
0.33
0.43
0.53
0.63
0.73
0.83
0.93
0.04
0.14
0.24
0.34
0.44
0.54
0.64
0.74
0.84
0.94
0.05
58965
48255
04635
15025
41505
82094
09574
00264
55844
45534
59224
77014
89893
75783
25673
38563
84553
54543
47533
43623
32713
04803
68992
75192
55382
77572
32862
29062
38352
69642
03042
48332
85722
05122
16512
98902
53402
69891
0.35
0.25
0.35
0.45
0.55
0.65
0.75
0.85
0.95
0.06
0.16
0.26
0.36
0.46
0.56
0.66
0.76
0.86
0.96
0.07
0.17
0.27
0.37
0.47
0.57
0.67
0.77
0.87
0.97
0.08
0.18
0.28
0.38
0.48
0.58
0.68
0.78
0.88
47391
76881
57381
98971
43471
48961
74561
22161
01751
01351
12941
44541
77141
02831
47431
73131
01821
29421
38121
38811
19511
70311
13011
26701
10501
74201
00001
0679
6259
9929
7709
2688
3568
9448
0528
7508
9687
6867
0.98
0.09
0.19
0.29
0.39
0.49
0.59
0.69
0.79
0.89
0.99
0.001
0.101
0.201
0.301
0.401
0.501
0.601
0.701
0.801
0.901
0.011
0.111
0.211
0.311
0.411
0.511
0.611
0.711
0.811
0.911
0.021
0.121
0.221
0.321
0.421
7057
4337
5617
0007
0486
3866
1356
3836
9326
8906
1695
7285
7965
0755
6445
6235
8025
4905
2894
3784
7674
3664
2654
4644
7634
4724
2814
3904
6004
1293
8383
7573
8763
1063
6253
2543