Trane Tracer UC400 - UC400 Controller Generated Diagnostics

54 VAV-SVX07F-EN
Troubleshooting
If the proper voltage is measured at the XFMR 24 Vac input and , and there is no voltage at
AI1 and
, replace the UC400 controller.
• Verify that the zone sensors ar
e not shorted out. Check the resistance across the wires.
Disconnect wires from the UC400 controller and zone sensor, ensuring that the ends are not
touching each other, and then measure resistance. It should be infinite or no conductivity. If
lower resistance is shown, then the wires are shorted together and need to be replaced.
Table 14. Zone Sensor Temperature Resistance.
Temperature (
o
F)
Thermostat Thumbwheel
Resistance (Ohms)
(a)
(a) Thumbwheel resistance checks are made at terminal 2 and 3 on the zone sensor. Temperature sensor resistance is measured
at terminal 1 and 2 of the zone sensor.
55
56
57
58
59
792
772
753
733
714
17.0
16.5
16.1
15.7
15.4
60
61
62
63
64
694
675
656
636
617
15.0
14.6
14.3
14.0
13.6
65
66
67
68
69
597
578
558
539
519
13.3
13.0
12.6
12.3
12.1
70
71
72
73
74
500
481
461
442
422
11.8
11.5
11.2
11.0
10.7
75
76
77
78
79
403
383
364
344
325
10.4
10.2
10.0
9.7
9.5
80
81
82
83
84
85
306
286
267
247
228
208
9.3
9.0
8.8
8.6
8.4
8.2
Sensor Resistance (k Ohms)