Why Your Furnace Keeps Turning On and Off All Day
If your furnace cycles on and off all day, do not ignore it. A few shorter cycles can happen during mild spring weather in Denver. But constant starting and stopping usually means the system needs attention.
May is a common time to notice this problem. You may be using your furnace less, but the system still has to run safely before you shut it down for summer.
GE Heating & Air has helped Denver homeowners with heating and cooling issues for more than 20 years. Here are the common reasons this happens and when to schedule a service.
What Is Short Cycling and Is It Normal?
A short-cycling furnace turns on, runs briefly, shuts off, then starts again soon after.
A normal furnace cycle often lasts about 10 to 15 minutes. That can change based on the outdoor temperature, your thermostat setting, insulation, and system size. In spring, your furnace may not need to run as long as it does during a cold January night.
But short cycling is different.
Your furnace may be short cycling if it:
- Starts and stops every few minutes
- Shuts off before your home feels warm
- Turns back on right away
- Runs many short cycles in one hour
- Leaves some rooms colder than others
Short cycling can raise energy use and add wear to furnace parts. It can also point to airflow trouble, thermostat problems, a dirty flame sensor, or a safety control issue.
How a Dirty Filter Causes HVAC Cycling Problems
A dirty filter is one of the first things to check when you have HVAC cycling problems.
Your furnace needs steady airflow to move heat through your home. When the air filter is clogged, air cannot pass through the system well. Heat builds up inside the furnace. When the temperature gets too high, the limit switch may shut the furnace off to protect it.
Then the furnace cools down and starts again.
That pattern can make it seem like the furnace has a major repair issue. Sometimes, the filter is the cause.
Check your filter before you call for service. Most homes need a new filter every one to three months. You may need changes more often if you have pets, dust, or allergy concerns.
If the filter is clean and the HVAC cycling continues, schedule service with GE Heating & Air. Call (303) 252-3185 or contact us to request help.
You can also ask about indoor air quality services if dust, dry air, or allergy symptoms are part of the problem.
Thermostat Problems That Make a Furnace Short Cycle
Thermostat problems can make a furnace short cycle even when the furnace itself is in good shape.
Your thermostat tells the furnace when to start and stop. If it reads the room wrong, the furnace may turn off too soon or run too often.
Common thermostat problems include poor placement, weak batteries, loose wiring, and incorrect settings. A thermostat near a sunny window can read warmer than the actual temperature of the room. A thermostat near a draft can read too cold. A thermostat near a supply vent may shut the furnace off before the rest of the house reaches the right temperature.
Check these items first:
- Set the thermostat to heat
- Set the fan to auto
- Replace the batteries
- Make sure vents near the thermostat are open
- Look for loose or damaged wiring if it is safe to do so
If the screen flickers, the settings reset, or the furnace still short-cycles, call a technician. Thermostat problems can seem small, but they can cause steady comfort issues.
Furnace Won't Stop Running? When to Call a Technician
If your furnace won't stop running, or it keeps turning on and off, it is time to call a technician.
Some causes are not safe for a homeowner to diagnose. An oversized furnace can heat the area around the thermostat too fast, then shut off before warm air reaches the whole house. A dirty flame sensor can interrupt burner operation. A heat exchanger issue needs prompt service because it can affect system safety.
Call GE Heating & Air if you notice:
- The furnace shuts off after only a few minutes
- The blower runs without stopping
- The furnace makes new sounds
- Your home never reaches the set temperature
- You smell unusual odors
- The system needs repeated resets
GE Heating & Air can inspect the system, explain the cause, and recommend the next step. Visit HVAC services to learn more, or use Schedule service through Contact us.
If warmer weather is around the corner, ask about air conditioning services during the same visit. Spring is a smart time to handle heating concerns and prepare your cooling system.
When your furnace cycles on and off, write down how often it happens and how long each cycle lasts. Then call GE Heating & Air for a clear diagnosis and a free estimate.