Help! My Heat Keeps Turning On and Off

To get your home properly warm, your heating system runs in cycles. The thermostat registers that the temperature has dropped below the threshold and calls for heat. The furnace turns on and runs until the temperature reaches the higher target. Then it shuts off and the house slowly drops in temperature until another heating cycle is triggered.

Sometimes, though, the cycle is interrupted. Instead of running until your whole home is evenly cozy and the target temperature is reached, the system shuts down early. Then, a moment later, it starts up. Then it shuts down again! This is called short cycling. If your heating system is doing it, you’ve got a problem, and it’s only getting worse. As soon as you notice short cycling, get heating repair in Janesville, WI. Here’s what causes short cycling.

Check and Clean Your Furnace Air Filter

It’s possible that the only “repair” you require is an unclogged air filter. This is something you should be doing regularly anyway, about once a month when your heating system is running every day. If there’s not enough air getting through the filter, the heat will build up excessively inside the furnace, causing the limit switch to shut the system down to prevent overheating.

When to Call for Professional Furnace Repairs

Once you’ve cleaned the filter and replaced it, see if your heat will stay on for full cycles. If not, it’s time to get a qualified technician to come take a look. There are a few different possibilities of what might be going wrong.

• Dust: If you haven’t had heating maintenance done this year, it could be that there’s so much dust in your furnace cabinet that it’s behaving like layers of insulation. When heat is kept in like that, components get too hot, and the limit switch is triggered. The problem might be entirely solved by a thorough professional cleaning and some lubrication by our team.

• Motor Malfunction: The blower fan is powered by a motor in order to distribute the heat. Perhaps the motor’s not running, so the heat is building up rather than being dissipated. Or perhaps there’s a mechanical or electrical issue causing overheating within the motor itself. Either of these can be resolved by our technicians.

• Faulty Limit Switch: Sometimes the only thing triggering the limit switch is a problem with the limit switch! If nothing else is wrong with your heating system, replacing the limit switch should resolve the short cycling issue.

Why Prompt Furnace Repair Is Important

Regardless of the root cause of the short cycling, it is critical to get the furnace repair done as promptly as possible. Why? Because short cycling is not just a symptom of an existing problem. It will soon turn into the cause of more problems if you let it continue.

The part of the heating cycle that uses the most energy and puts the most strain on the various components of the system is the startup. And your heating system is doing that over and over, perhaps a dozen times an hour instead of three. Components are experiencing a lot of extra wear and tear. And an unreasonable amount of energy is being used. Your utility bills will be through the roof.

Don’t let this happen to you. We’ll get your system sorted out right away.

Frequently Asked Questions

Question: Why does my furnace keep turning on and off?
Answer: A furnace that repeatedly starts and stops before completing a normal heating cycle is experiencing short cycling, which can be caused by restricted airflow, overheating, or component problems. A dirty air filter is one common cause because it can trap heat inside the furnace and trigger the system’s safety limit switch.

Question: Can a dirty air filter cause my furnace to short cycle?
Answer: Yes, a clogged air filter can restrict airflow and allow excessive heat to build up inside the furnace, causing the limit switch to shut the system down. Checking and replacing a dirty filter is a simple first step if your heating system keeps turning on and off unexpectedly.

Question: What causes furnace short cycling if the air filter is clean?
Answer: If replacing the air filter does not solve the problem, possible causes include excessive dust inside the furnace, a malfunctioning blower motor, or a faulty limit switch. A qualified HVAC technician can inspect these components, determine why the system is overheating or shutting down, and recommend the proper repair.

Question: Is furnace short cycling bad for my heating system?
Answer: Yes, short cycling causes the furnace to go through repeated startups, which use extra energy and place additional strain on system components. Allowing the problem to continue can increase wear and tear, raise utility bills, and potentially lead to more expensive heating repairs.

Question: When should I call for furnace repair if my heater keeps cycling?
Answer: If your heater continues turning on and off after you replace or clean the air filter, it is time to have the system professionally inspected. Prompt repairs can address the underlying cause before repeated short cycling causes additional component damage, wastes more energy, or leads to a larger breakdown.

You can always count on 24-Hour Home Comfort Services, your heating and cooling specialists.