3 Reasons Why Your Furnace Turns On And Off Constantly

One of the most common problems homeowners often face with their furnace is called short cycling. This is when your furnace turns on and off frequently. This start-and-stop cycle can keep your home from properly warming up and may also damage your furnace itself. If short cycling is not corrected, it can increase your energy bills and lead to costly furnace repairs. Here’s what may be causing your furnace to short cycle and what you can do about it.

1.Low airflow

Short cycling could be caused by low airflow. There are several issues that can cause low airflow. A dirty air filter or blocked or closed registers could be restricting airflow. If your filter becomes dirty and clogged, heat can build up on the furnace’s heat exchanger, causing it to overheat and shut off. Change your filter regularly according to manufacturer’s instructions, usually every 90 days unless you have pets or allergies. If you have pets or allergies, you should be changing air filters every 60 days, or less if your allergies are severe. Also, check all registers to make sure they are open and unblocked by furniture, rugs or other obstructions. You should keep all your vents open, even in the rooms you don’t use. If your heat exchanger doesn’t get enough air, it can’t transfer enough heat Then that heat builds up and could end up causing your furnace to short cycle.

2.Defective thermostat

Another common cause of a short cycling furnace isn’t your furnace at all. Your thermostat which controls the heating system might be malfunctioning. When your thermostat malfunctions, it can signal to your furnace that the set temperature in the room has been met, causing the furnace to prematurely turn off. A number of things could cause your thermostat to malfunction. If your thermostat uses batteries, replace them. If it is not a battery issue, it may have faulty wiring, or the location could be the problem.

3.Over-sized furnace

A furnace that is too big for the space will likely short cycle. Why? The larger unit will heat the house too quickly then abruptly shut off. Once the temperature drops, the cycle is quickly repeated. One possible solution is to reduce the cycles per hour heat setting on an advanced thermostat (say, from five to three). The trade-off is wider temperature swings. Otherwise, you would have to replace your furnace with a new unit that’s properly sized for your home.

That’s not all

There could be other issues causing your furnace to cycle on and off frequently. It could be defective fan limit switch, a corroded flame sensor or a poorly designed duct system. Problems such as these require the attention of a qualified HVAC professional. So, if your experiencing a furnace that is short cycling contact us here at Horne.

To help prevent costly maintenance issues and ensure optimal performance, have your heating system cleaned and inspected at least once a year.