A furnace fan that does not shut off may cause harm to the entire heating system in the home. A couple of simple steps can help check to see if repairs can be completed at home or if professional help is required. Resetting the thermostat, clearing any clogs and replacing the filter if worn or damaged are all easy fixes for basic problems. If these do not help, it is best to get a professional opinion./
Make sure the problem does not lie with the thermostat being set to "on," which means the fan operates continuously. If it is, try resetting the thermostat to see if that solves the problem.
Look for any clogs in the filter. A clogged filter may cause severe damage to the limit switch. The limit switch senses the temperature inside the furnace, and it shuts off the fire when the temperature becomes too high as a safety, only allowing it to come back on once it has cooled sufficiently. Trying to fix the limit switch rather than replacing it may cause safety issues.
Check and change the filter frequently to reduce energy costs, reduce potential damage to the furnace and keep the air in the house clean. When a filter becomes too clogged, it restricts the air flow through the furnace, so the furnace works too hard to move the heat away. Filter pieces may also get caught in the blower wheel and need to be removed.
Troubleshooting a furnace that does not turn off begins with examining it for a malfunction or clog. The thermostat, air filter and fuel supply can all be examined in less than an hour. If the error cannot be identified during these steps, contact your manufacturer and have a certified technician examine the furnace.Full Answer >
Lighting a gas furnace involves turning off the pilot valve, lighting the pilot with a long fireplace match, then turning the gas knob to the On position. This process takes less than half an hour.Full Answer >
The on-and-off cycling of your furnace depends on many factors, including proper system sizing, thermostat settings and weather conditions. Cycles that are too close together may indicate an oversized system.Full Answer >
On average, a furnace will cycle every 10 to 20 minutes. The amount of time between cycles is dependent on a number of factors, including the outside air temperature and the temperature at which the thermostat is set.Full Answer >