The following test procedure works on the TS-1 Temperature Sensor used with the CTI, TTI, TTT and RFC series devices.

The test requires a small 5VDC power supply (only a few milliAmps required) and a volt meter capable of measuring to a 1/100 of a volt DC.

If you suspect that a temperature sensor is damaged it can be removed from the system and tested externally. This test is only valid for sensors using an LM34 (Fahrenheit) or LM35 (Celcius) device as the sensing element. The sensing element is the small, black TO-92 packaged device on the sensor PCB.

Disconnect the sensor cable from the device (CTI, TTI, TTT, RFC, etc.) before continuing with the test. This is very important!

Once you have access to the three leads of the sensor and have isolated them from the main device:

• connect the positive lead of the meter to the sensor "S" lead
• connect the negative lead of the meter to the sensor "G" lead
• connect the sensor "G" lead to the low side of the power supply
• connect the sensor "+" lead to the positive side of the power supply

Set the meter to measure DC voltage and apply main power to the 5VDC supply.

If the sensor is working properly, the volt meter will read one 1/100 of a volt per degree for the ambient temperature at the sensing device. For example, if the ambient air temperature is 75 degrees F, the meter will read 0.75 volts +/- 0.02 volts.

If the voltage varies from actual temperature reading by more than several 1/100ths of a volt, then sensor has probably been damaged. If the meter reading fluctuates more than a couple 1/100ths of a volt, the sensor is probably picking up noise or has been damaged.