Troubleshooting the Lennox G12

Be safe when working around your furnace.

The Lennox G12 is a gas-powered heater for homes and businesses. While these gas furnaces are designed to be reliable and easy to use, they are not without problems. If you find that your Lennox G12 furnace is no longer providing the warmth you need, it is best to use a step-by-step approach when troubleshooting the problem. Many causes lead to a malfunctioning Lennox G12 furnace, so checking each possible problem is the best way to proceed.

Instructions

1. Verify that the electrical outlet is working by plugging a lamp or other appliance into it Reset the breaker or replace the fuse on the Lennox G12 if necessary.

2. Check the pilot light to see if it has gone out. The furnace will not operate if the pilot light is not on. If the pilot light is not lit, turn the thermostat to the lowest setting, turn off power to the furnace and open the access panel. The pilot light is located just inside the access door, and the thermostat is located on the furnace itself. Push the gas valve to the off setting. Wait five minutes for the gas to clear, then turn the knob to the pilot setting and hold the gas knob while lighting the pilot with a match. Wait for the pilot light to come on, then turn the knob to the on position.

3. Turn the furnace off and flip up the cover of the filter access panel if the Lennox G12 lights but does not heat well. Grasp the filter by the lip on the front of it and carefully slide it out of the furnace. Clean the filter using a rag that has been soaked in water with enough detergent to form suds. Replace the filter if you cannot get it clean with the detergent and water.

4. Adjust the thermostat if the temperature is too cold or too warm. Turn the knob on the furnace to adjust the temperature control. Contact an authorized Lennox service center if the furnace still does not operate properly.

Tips & Warnings

• Always smell for gas before working on your Lennox furnace. Leave the house and call the gas company immediately if you smell gas

References

• Lennox: G12 User Manual