Filthy Air Filter 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.

What causes my furnace to short cycle?

What Causes Short Cycling? Furnaces have built-in safety systems that prevent dangerous situations like fires, carbon monoxide leaks, or gas leaks. The most likely cause of short cycling is the fan limiter, which prevents fires and furnace damage by shutting the system down if the heat exchanger becomes too hot.

Why does my furnace cycle every 5 minutes?

Blocked Exhaust Vent
This is another cause of a furnace overheating and short cycling. Short cycle time: 1-5 minutes. This issue can be dangerous too, since deadly carbon monoxide is dispersed through the vent. If it is blocked, the gas won’t escape, and it can leak out of the furnace and into your home.

How do you fix short cycling?

How To Stop and Prevent Short-Cycling

  1. Check your air filter. Believe it or not, a clogged air filter can cause a wide variety of air conditioning issues. …
  2. Check your thermostat placement. …
  3. Check your air conditioner’s refrigerant levels. …
  4. Replace the low-pressure control switch. …
  5. Check the compressor.

Why does my furnace keep cycling on and off?

So, if your furnace keeps turning off and on too quickly, your thermostat might be malfunctioning or broken. There are several things that could be causing your thermostat to not work properly. The wiring could be old and need replacing, it might need new batteries, or it could be the location of your thermostat.

How do you fix a short cycle on a furnace?

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.

Can a bad thermostat cause your furnace to short cycle?

Thermostat Troubles Can Cause Short Cycling
Your furnace or central air conditioner spends a good amount of energy simply turning on and off, which is why you want yours to run for at least 15 minutes at a time before shutting off.

Can a bad blower motor cause short cycling?

Air handler defects ranging from a dirty air filter to dirty blower or wrong blower speed can prevent the furnace from producing enough heat rise across the heat exchanger, causing overheating and short cycling at the heating furnace.

How do you know if your furnace is short cycling?

Room and Thermostat Difference
If the temperature reading of the room steadily increases during the heating cycle but stops short of the set temperature—and does so continuously—then the furnace is short cycling.

What can cause short cycling?

What Causes Short-Cycling?

  • A clogged air filter.
  • An oversized or undersized air conditioner.
  • Low refrigerant charge due to leaks.
  • Air escaping through a leaky ventilation system.
  • Miscalibrated thermostats reading incorrect temperatures.

Why does my furnace turn on every 10 minutes?

Bad Thermostat: If your thermostat has a problem, it can cause your furnace to run cycles that are either too long or too short. If the thermostat is sensing the incorrect temperature and not sending a cut-off signal soon enough, or if the battery is dying, your thermostat can cause your furnace to run erratically.

Will dirty air filter cause short cycling?

Short-cycling = wasted energy, increased utility bills
A dirty filter can cause these cycles to become more frequent and less effective. This results in uneven cooling, wasted energy, increased utility bills and unnecessary changes in your home’s temperature.

How do I know if my furnace flue is clogged?

How to tell if your exhaust vent is blocked

  1. Furnace doesn’t heat the air. By far, the most common symptom of a blocked exhaust vent is a furnace that doesn’t heat up. …
  2. Furnace heats up for a little while, then shuts off. …
  3. Furnace cover panel gets hot. …
  4. Bad smells when your furnace is heating.

How do I unclog my furnace?

How to unclog your furnace’s condensate drain

  1. Check to see how bad the clog is. Take a look in your drain pan and outside where the drain line goes to see if it is something simple to fix. …
  2. Remove the clog by hand. …
  3. Use a drain brush or drain snake. …
  4. Use a wet/dry vacuum. …
  5. Use a drain gun.

How often should furnace flue be cleaned?

A flue that is unable to properly vent can become filled with dangerous, and even deadly vapors that will eventually leak right back into your home. Therefore, it is essential that you have your flue inspected and properly cleaned at least once a year.

How do you unclog a furnace vent pipe?

Scrub the inside free of any dust and debris; then use the handheld vacuum to get out as much as you can. Wipe it clear with a rag or soft cloth and then replace the cap. Cut away any branches or remove any object that might be obstructing the pipe and creating debris. The vent should always be clear.

How do you tell if your vents are clogged?

The biggest symptom of clogged air ducts in your home is a difference in temperatures. This is most likely to occur if you set your whole-home thermostat to the desired temperature and then notice that one room isn’t as warm or cool as the others.

What happens if furnace exhaust is blocked?

Carbon monoxide is found in fumes produced anytime your furnace is working. It’s important to keep your furnace vents, intakes valves and chimney snow free. Blocked vents could cause carbon monoxide to build up in your home and cause carbon monoxide poisoning.