Zonex DigiTract 4-2 - TROUBLESHOOTING AND SERVICE CHECKS; LAS VOLTAGE-TEMPERATURE CONVERSION CHART

°F. DC Volts °F. DC Volts °F. DC Volts °F. DC Volts
40 2.775 56 2.864 72 2.953 88 3.042
41 2.781 57 2.870 73 2.959 89 3.048
42 2.787 58 2.875 74 2.964 90 3.053
43 2.792 59 2.881 75 2.970 91 3.059
44 2.798 60 2.887 76 2.975 92 3.064
45 2.803 61 2.892 77 2.981 93 3.070
46 2.809 62 2.898 78 2.987 94 3.075
47 2.814 63 2.903 79 2.992 95 3.081
48 2.820 64 2.909 80 2.998 96 3.087
49 2.825 65 2.914 81 3.003 97 3.092
50 2.831 66 2.920 82 3.009 98 3.098
51 2.837 67 2.925 83 3.014 99 3.103
52 2.842 68 2.931 84 3.020 100 3.109
53 2.848 69 2.937 85 3.025 101 3.114
54 2.853 70 2.942 86 3.031 102 3.120
55 2.859 71 2.948 87 3.037 103 3.125
°F. DC Volts °F. DC Volts °F. DC Volts °F. DC Volts
104 3.131 119 3.214 134 3.298 149 3.387
105 3.137 120 3.220 135 3.303 150 3.392
106 3.142 121 3.225 136 3.309 151 3.398
107 3.148 122 3.231 137 3.314 152 3.403
108 3.153 123 3.237 138 3.320 153 3.409
109 3.159 124 3.424 139 3.325 154 3.409
110 3.164 125 3.248 140 3.331 155 3.414
111 3.170 126 3.253 141 3.337 156 3.420
112 3.175 127 3.259 142 3.342 157 3.425
113 3.181 128 3.264 143 3.348 158 3.431
114 3.187 129 3.270 144 3.353 159 3.437
115 3.192 130 3.275 145 3.359 160 3.442
116 3.198 131 3.281 146 3.364
117 3.203 132 3.287 147 3.375
118 3.209 133 3.292 148 3.381
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DIGITRACT 4-2 TROUBLESHOOTING / SERVICE CHECKS
DIGITRACT 4-2 LAS VOLTAGE – TEMPERATURE CONVERSION CHART
Malfunction Probable Cause Corrective Action
All thermostats will not call Loss of 24V ac on R and C Repair power source
Will not initiate cooling cycle Controller in heat mode 15 minute delay prior to changeover
Controller in changeover from heat mode 3 minute purge cycle must complete
LAS polarity incorrect Red lead to + terminal, white to – terminal
Cooling calls short cycle LAS shorted (0V dc on + and – w/ LAS installed) Replace LAS
LAS wiring shorted (0V dc on + and – w/ LAS installed) Repair LAS wiring
Controller failure (0V dc on + and – w/ LAS removed) Replace controller
Thermostat has cooling anticipator (compensator) Remove anticipator
Air flow too low over evaporator Isolate and correct air flow problem
Bypass damper opening prematurely Adjust bypass damper closed w/ all zone dampers open
LAS out of calibration Recalibrate LAS
Will not initiate heat calls Controller in cool mode 15 minute delay prior to changeover
Controller in changeover from cool mode 3 minute purge cycle must terminate
LAS polarity incorrect Red lead to + terminal, white to – terminal
LAS electrical interference (Applicable to spark ignition) Install shielded cable to LAS, terminate shield on C terminal ONLY
Heating calls short cycle LAS open (5V dc on + and – w/ LAS installed) Replace LAS
LAS wiring open (5V dc on + and – w/ LAS installed) Repair LAS wiring
Heating anticipator incorrectly set Set anticipator to lowest setting
Bypass damper opening prematurely Adjust bypass damper closed w/ all zone dampers open
LAS out of calibration Recalibrate LAS
Zone dampers will not close Loss of 24V ac on TR1 And TR2 Repair power source
Transformer VA too low Replace w/ correct transformer
Dampers incorrectly wired Correct damper wiring
No output on damper terminal(s) Cycle power to controller. Verify thermostat inputs are correct.
If problem persists, replace controller
Zone damper remains closed Zone not calling while mode is active Initiate thermostat call
Triac shorted (Continuous 24V ac @ damper terminals) Replace controller
W2 will not energize Discharge air temperature above 88° F. Normal operation
(DTHP4-2 only) Relay contact failure (W2 LED on) Replace controller
Bypass damper opening prematurely Adjust bypass damper closed w/ all zone dampers open
Controller in cool mode Verify jumper JU1 position
Blower runs continually Fan operation selected on any thermostat Verify fan switch on all thermostats
Fan relay contacts in controller seized Replace controller, check 24 V AC
Using a digital volt-ohm meter, place the red lead on the + terminal and the black lead on the - terminal of the equipment terminal strip. Set the voltmeter to the 20VDC scale, and con-
vert the measured voltage to its corresponding temperature.