By Dwight Barnett
The furnace that worked just fine last year might need some service this year. Here are a few tips to help guide you in the safe operation of your furnace.
* Change the filter. This is one of the easiest maintenance items you can do. A dirty filter not only blocks airflow, which increases the load on the fan, but the dust and dirt that pass through a dirty filter build up inside the ductwork, further reducing the efficiency of the whole system. Filters should be properly sized to fit the filter rack near the fan and there should be a filter cover to prevent cold air from entering the ductwork.
* For older furnaces that have pilot lights:
1. If the pilot light will not stay on, replace the thermocouple tube located between the main gas valve inside the furnace and the pilot light.
2. Check to make sure the pilot-light flame is burning blue and not orange. Orange flames indicate incomplete combustion of gas, and that the furnace needs adjustment. Also check the color of all burners when the furnace is on and heating. They should also be blue and steady, not flickering. A flickering flame could indicate a more serious problem with the furnace — and that it should be inspected by an HVAC (heating, venting, air conditioning) technician.
3. With the furnace operating on the heat cycle, hold a candle or match next to the opening for the flue at the top of the furnace to see if the flue has a draft to carry the fumes from the burners out of the home. If the flue does not draft, shut the unit off and call an HVAC technician right away. A furnace that does not draft properly can release hazardous carbon monoxide gas into the home.
4. Check for rust or rust particles on the surface of the burners. If the burners are partially blocked by residue buildup, the furnace will not heat efficiently, and will waste energy. Vacuum the burner chambers using a crevice tool or call an HVAC technician.
* For newer furnaces with no pilot light:
1. Make sure the igniter is working. The igniter is a ceramic element that glows red hot to ignite the gas when the furnace first comes on. If the igniter is broken or damaged, the furnace will not work. Replacement is a simple DIY project.
2. Make sure the draft-inducement fan is working. The small fan is located at the bottom of the flue pipe and forces the fumes through the flue to the outside. If the fan is not working the furnace will not come on. Contact an HVAC technician.
3. If the draft-inducement fan is connected to a PVC flue pipe, you have a high-efficiency-condensing furnace. Check inside the furnace cabinet for any signs of condensate leaks or rust stains. Condensate water from a high-efficiency furnace is acidic, and can cause a chemical burn if improperly handled. Contact an HVAC technician for repairs.