Specifications

GT-PCS Split Units - 60Hz Puron
®
Created: 29 Aug., 2013
58
Troubleshooting
Table 19: Nominal resistance at various temperatures
Temp (ºC) Temp (ºF)
Resistance
(kOhm)
Temp (ºC) Temp (ºF)
Resistance
(kOhm)
-17.8 0.0 85.34 55 131.0 2.99
-17.5 0.5 84.00 56 132.8 2.88
-16.9 1.5 81.38 57 134.6 2.77
-12 10.4 61.70 58 136.4 2.67
-11 12.2 58.40 59 138.2 2.58
-10 14.0 55.30 60 140.0 2.49
-9 15.8 52.38 61 141.8 2.40
-8 17.6 49.64 62 143.6 2.32
-7 19.4 47.05 63 145.4 2.23
-6 21.2 44.61 64 147.2 2.16
-5 23.0 42.32 65 149.0 2.08
-4 24.8 40.15 66 150.8 2.01
-3 26.6 38.11 67 152.6 1.94
-2 28.4 36.18 68 154.4 1.88
-1 30.2 34.37 69 156.2 1.81
0 32.0 32.65 70 158.0 1.75
1 33.8 31.03 71 159.8 1.69
2 35.6 29.50 72 161.6 1.64
3 37.4 28.05 73 163.4 1.58
4 39.2 26.69 74 165.2 1.53
5 41.0 25.39 75 167.0 1.48
6 42.8 24.17 76 168.8 1.43
7 44.6 23.02 77 170.6 1.39
8 46.4 21.92 78 172.4 1.34
9 48.2 20.88 79 174.2 1.30
10 50.0 19.90 80 176.0 1.26
11 51.8 18.97 81 177.8 1.22
12 53.6 18.09 82 179.6 1.18
13 55.4 17.26 83 181.4 1.14
14 57.2 16.46 84 183.2 1.10
15 59.0 15.71 85 185.0 1.07
16 60.8 15.00 86 186.8 1.04
17 62.6 14.32 87 188.6 1.01
18 64.4 13.68 88 190.4 0.97
19 66.2 13.07 89 192.2 0.94
20 68.0 12.49 90 194.0 0.92
21 69.8 11.94 91 195.8 0.89
22 71.6 11.42 92 197.6 0.86
23 73.4 10.92 93 199.4 0.84
24 75.2 10.45 94 201.2 0.81
25 77.0 10.00 95 203.0 0.79
26 78.8 9.57 96 204.8 0.76
27 80.6 9.16 97 206.6 0.74
28 82.4 8.78 98 208.4 0.72
29 84.2 8.41 99 210.2 0.70
30 86.0 8.06 100 212.0 0.68
31 87.8 7.72 101 213.8 0.66
32 89.6 7.40 102 215.6 0.64
33 91.4 7.10 103 217.4 0.62
34 93.2 6.81 104 219.2 0.60
35 95.0 6.53 105 221.0 0.59
36 96.8 6.27 106 222.8 0.57
37 98.6 6.01 107 224.6 0.55
38 100.4 5.77 108 226.4 0.54
39 102.2 5.54 109 228.2 0.52
40 104.0 5.33 110 230.0 0.51
41 105.8 5.12 111 231.8 0.50
42 107.6 4.92 112 233.6 0.48
43 109.4 4.72 113 235.4 0.47
44 111.2 4.54 114 237.2 0.46
45 113.0 4.37 115 239.0 0.44
46 114.8 4.20 116 240.8 0.43
47 116.6 4.04 117 242.6 0.42
48 118.4 3.89 118 244.4 0.41
49 120.2 3.74 119 246.2 0.40
50 122.0 3.60 120 248.0 0.39
51 123.8 3.47 121 249.8 0.38
52 125.6 3.34 122 251.6 0.37
53 127.4 3.22 123 253.4 0.36
54 129.2 3.10
General
If operational diffi culties are encountered, perform
the preliminary checks below before referring to the
troubleshooting charts.
• Verify that the unit is receiving electrical supply power.
• Make sure the fuses in the fused disconnect switches are
intact.
After completing the preliminary checks described above,
inspect for other obvious problems such as leaking
connections, broken or disconnected wires, etc. If everything
appears to be in order, but the unit still fails to operate
properly, refer to the “DXM2 Troubleshooting Process
Flowchart” or “Functional Troubleshooting Chart.”
DXM2 Board
DXM2 board troubleshooting in general is best summarized
as verifying inputs and outputs. After inputs and outputs
have been verifi ed, board operation is confi rmed and the
problem must be elsewhere. Below are some general
guidelines for troubleshooting the DXM2 control.
Field Inputs
Conventional thermostat inputs are 24VAC from the
thermostat and can be verifi ed using a voltmeter between C
and Y1, Y2, W, O, G. 24VAC will be present at the terminal
(for example, between “Y1” and “C”) if the thermostat is
sending an input to the DXM2 board.
Proper communications with a thermostat can be verifi ed
using the Fault LED on the DXM2. If the control is NOT
in the Test mode and is NOT currently locked out or in
a retry delay, the Fault LED on the DXM2 will fl ash very
slowly (1 second on, 5 seconds off), if the DXM2 is properly
communicating with the thermostat.
Sensor Inputs
All sensor inputs are ‘paired wires’ connecting each
component to the board. Therefore, continuity on pressure
switches, for example can be checked at the board
connector. The thermistor resistance should be measured
with the connector removed so that only the impedance of
the thermistor is measured. If desired, this reading can be
compared to the thermistor resistance chart shown in Table
19. An ice bath can be used to check the calibration of the
thermistor.