Auto-Zone Control Systems Auto-Zone CV & CV-EX Systems Installation & Operation (Version 01C) - Manual (Page 111)

Auto-Zone CV & CV-EX
Section 4
Start-Up and Troubleshooting 4-33
Room Sensor
Room Sensor Troubleshooting Checklist
Begin troubleshooting by locating the general problem in the list below
Room Sensor reading incorrectly
Is the sensor near a source of heat or a cold draft? Location is a common problem.
The sensor should be mounted on an inside wall away from heat sources and in a
location with adequate room air circulation.
Is the resistance reading correct? Check with the Temperature/Resistance Chart in
this section.
Is wiring correct? Check for errors.
Meter the Room Sensor
To meter the Room Sensor:
1. With the sensor connected to the controller, power up the controller. Using your
meter, check the voltage at the controller terminal block where the sensor is con-
nected. Use the supplied Temperature Sensor Voltage & Resistance Chart to
see if the sensor is within a reasonable range. Readings which are much too high
or too low generally indicate wiring problems or a defective sensor.
2. Unplug the room sensor terminal block. Using your meter, check the resistance of
the unplugged terminal block. Use the supplied Temperature/Resistance Chart
to see if the sensor is within a reasonable range. Readings which are much too
high or too low generally indicate a wiring problem or a defective sensor.
To meter the Slide Adjust (optional):
Use your ohmmeter to check the resistance between the room sensor GND wire
and the AUX1 terminal on the unplugged terminal block.
The resistance for various positions of the slider on the sensor should be as follows:
Full UP position 15K Ω (± 500 Ω)
MID position 12.5K Ω (± 500 Ω)
Full DN position 10K Ω (± 500 Ω)