A dirty air filter is the most common cause of short-cycling. If your air filter is clogged with dirt, it won't allow proper air flow to the heat exchanger. That can cause the furnace to overheat and forces the high limit switch to ride to the rescue by shutting the furnace off.
How do I stop my furnace from short cycling?
The easiest way to fix a furnace that is short cycling is to remove the flame sensor to clean it . Use a sponge or brush to remove the dirt from the sensor. After the part is clean, follow the manufacturer's instructions to insert the flame sensor into the furnace.
How do you fix short cycling?
- Check your air filter. ...
- Check your thermostat placement. ...
- Check your air conditioner's refrigerant levels. ...
- Replace the low-pressure control switch. ...
- Check the compressor.
Is it bad for your furnace to short cycle?
A short cycling furnace can cause your home heating system to break down prematurely , which can be a big problem during the winter months. If your furnace is short cycling and you can't seem to get the problem under control, contact the heating contractors at a professional furnace repair service today.
What do I do if my heater is short cycling?
If you suspect this is the reason your furnace is short cycling, it is imperative that you contact an HVAV professional to repair the unit . Restricted airflow is typically the cause of overheating which may be due to a dirty air filter or interior vents, or because roof exhaust vent is blocked.
How long can a furnace short cycle?
Short cycle time: 3-7 minutes in most cases.
When a furnace is too big, it can short cycle – start, heat up air very quickly that reaches the thermostat, and then shut down. Compare this to driving a car.
Why does my furnace turn on and off every few minutes?
If your furnace turns off after a few minutes, there is a good chance it is caused by a faulty or dirty flame sensor . This vital component is designed to keep an eye on the gas burner. When it cannot sense that burner, the furnace runs then shuts off and starts again.
What is considered short cycling?
Short-cycling is a term for when an air conditioner shuts down its cooling cycle prematurely, only to start back up again a short time later . If you have noticed that your air conditioner's compressor is turning on and off rapidly, it is probably short-cycling and you need to have it repaired.
Can a bad thermostat cause short cycling?
A faulty thermostat can be a possible culprit for short cycling. If you're experiencing a furnace short cycling, the first and easy thing you can do is check your thermostat to see if it's performing correctly. Many times, a homeowner may forget to switch their thermostat over to the heating mode.
How do you know a thermostat is bad?
- Your HVAC Keeps Turning On or Off. ...
- Faulty Thermostat Readings. ...
- Suspiciously High Energy Bills. ...
- Constant Temperature Shifts. ...
- Thermostat Is Too Old. ...
- Thermostat Fails to Respond to Changed Settings. ...
- Your HVAC System Short Cycles. ...
- Know When to Replace Your Thermostat.
Can a dirty filter cause a furnace to short cycle?
A dirty air filter is the most common cause of short-cycling. If your air filter is clogged with dirt, it won't allow proper air flow to the heat exchanger. That can cause the furnace to overheat and forces the high limit switch to ride to the rescue by shutting the furnace off.
How do you know if your furnace is overheating?
- You notice a “hot” or burning smell coming from the vents. ...
- You hear strange noises or loud humming coming from the furnace. ...
- You notice the furnace cycling off without starting again.
How do I know if my furnace flame sensor is bad?
- The furnace lights but then shuts down after a few seconds (short cycles)
- The porcelain on the flame sensor is cracked.
- The flame sensor is sooty or corroded.
Why does my furnace turn on then off right away?
Your furnace turns on, runs for a few minutes and then shuts off. ... Typically, a furnace keeps turning off and on (or “short cycling”) like this because of one of these problems: Heat exchanger is overheating due to low airflow. Dirty flame sensor rod.
How long should a furnace run per cycle?
With all that being said, if there are no extreme factors involved, the average run time for a furnace is 10-15 minutes per cycle . Your furnace may need to run two to three times an hour to maintain your desired temperature if your home has average insulation.
How many times should a furnace cycle in an hour?
On average, furnaces should kick on and turn off anywhere from three to eight times per hour . However, if your furnace turns on and off more frequently, don't assume the furnace is short cycling just yet.
