How to Troubleshoot a Model 3000 Digital Thermostat

Fortunately, any given symptom has only a limited number of causes, So once a symptom is identified the source problem can typically be easily diagnosed and remedied.

1. Check the thermostat display to see if it indicates that the system is off, if the thermostat does not turn on the heating/cooling system. If the system is off, move the selector switch to either the "HEAT" or "COOL" position. The system will resume normal operation after a 5-minute protection cycle.

2. Check that the wiring of the thermostat is not reversed if the heating option turns on the air conditioner and the cooling option turns on the heater. Do this by removing the cover of the thermostat and checking that the heat control wire is connected to the connector labeled "W" and the cool control wire is connected to the connector labeled "Y."

3. Change the temperature differential settings if the heating or cooling system turns on too frequently or not enough. Do this by holding down the up and down arrows on the front panel for 4 seconds. When the display shows "SET D1 X" use the up and down buttons to set the differential higher or lower than the current setting. This changes when the thermostat turns the system on based on how much higher or lower the room temperature is in comparison to the set temperature. For example, if the differential is set to .5 then the heater will be turned on when the thermostat reads a temperature .5 degrees less than the set temperature and the cooling will turn on when it reads .5 degrees above the set temperature.

4. Replace the batteries if the low battery indicator is displayed

5. Unlock the keypad, if you cannot set the thermostat, by pressing the up and down arrow buttons at the same time.

6. Set the fan to "AUTO" if it's not already set this way. Otherwise, the fan will run continuously even when the cooling or heating system is not running.

7. Wait until the surrounding temperature returns to a point between 45 and 90 degrees Fahrenheit if the thermostat displays "HI" or "LO." The thermostat displays these indicators when the temperature is higher or lower than it is able to measure.