Why Your Furnace Keep Turning On and Off
While you enjoy the warmth afforded by Bradenton, Florida’s coastal location, you still rely on your furnace to keep comfortable during the winter months. A furnace that is frequently turning on and off can drive up your utility bills and signal some underlying problems you need to address.
At Bradenton One Hour Air Conditioning & Heating, our expert HVAC technicians can diagnose what’s causing your furnace to short-cycle and fix it quickly. This guide explains the most common reasons why your furnace might be short-cycling and some steps you can take to address the issue.
What Is Short-Cycling?
In the HVAC industry, a furnace’s repeated turning on and off is called short cycling. A furnace should turn on and off between two and four times per hour to keep your home’s temperature at a comfortable level.
When it turns on and off more frequently than that, something is causing each heating cycle to be cut short. This can quickly drive up your energy bills and should be addressed.
Common Causes of Furnace Short Cycling and What to Do
1. Dirty Filter
A dirty or clogged air filter is the most common reason why your furnace might be short-cycling. Dirt and humidity restricts the flow of air through the filter and causes your furnace to work harder to maintain the temperature in your home.
What to do: Check your filter. If it’s dirty, change it. Make sure you change your air filters frequently. For a standard filter, you should change it each month.
If you don’t know where to find the filter, check the owner’s manual. Make sure you replace your filter with one that’s the correct size.
2. Obstructed Vents or Registers
Your home’s return ducts draw air into your furnace, and the registers allow heated air to circulate through your home. If these are blocked by furniture, curtains, or other obstructions, the air will not be able to flow freely, and can cause your furnace to short-cycle.
What to do: Walk around your home and make sure each return duct and register is free from obstructions. Each should have around a three to five-foot radius around it to allow for unrestricted airflow.
3. Faulty Thermostat or Incorrect Thermostat Settings
A faulty thermostat might not accurately detect your home’s temperature. It might then send incorrect information to your furnace, causing it to turn off and on frequently. Similarly, a miscalibrated thermostat can cause short cycling.
What to do: Check your theromstat. First, make sure it’s turned to the heat setting if it’s a standard, non-programmable thermostat. You should also check your thermostat’s batteries and change them if needed.
If you need help with recalibrating or fixing your thermostat, call the HVAC professionals at Bradenton One Hour Air Conditioning & Heating.
4. Dirty Flame Sensor
Your furnace’s flame sensor determines how much gas should flow into your gas furnace. Over time, the flame sensor can become dirty, causing it not to work properly.
A dirty flame sensor can’t tell whether your furnace’s flame is using the gas and will cause the valve to stop sending gas to the burner. This is a safety feature designed to prevent an excess gas buildup.
What to do: If you suspect that your furnace’s flame sensor could be dirty, schedule regular maintenance with Bradenton One Hour Air Conditioning & Heating.
5. Damaged Fan Limit Switch
Your furnace’s fan limit switch controls how frequently the blower cycles on and off. If it’s damaged or has a short circuit, it can cause your furnace to short-cycle.
A shorted-out fan limit switch might require you to reset the switch or the furnace itself. It locks out to prevent carbon monoxide from building up in your home.
What to do: While you can test the fan limit switch with a multimeter after turning off the power and gas to your furnace, it’s best to call a professional. Working with electricity and gas should be left to the HVAC experts at Bradenton One Hour Air Conditioning & Heating to prevent safety issues.
6. Improperly Sized Furnace
If you recently replaced your furnace, and your new one is turning on and off frequently, it might not be the correct size for your home. If it’s too big for your home, it might heat up your home too quickly and turn off early. On the other hand, if your furnace is too small, it will short-cycle as it struggles to heat up your home.
What to do: In either case, the professionals at Bradenton One Hour Air Conditioning & Heating can check your furnace and help you determine the right size for your home.
Trust Our Expert HVAC Technicians
Short cycling can drive up your heating bills and reduce your furnace’s lifespan. If you notice that your furnace is turning on and off frequently, you should call the HVAC experts at Bradenton One Hour Air Conditioning & Heating. We can quickly diagnose and fix the underlying problem. When you trust us, we are always on time, or you don’t pay a dime.
Call us today at (941) 290-6852 to schedule your appointment with our knowledgeable HVAC team at Bradenton One Hour Air Conditioning & Heating.
