Why does my furnace work intermittently?
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.
Why does my furnace not come on sometimes?
If your furnace is not turning on you should first check if the filter is clean. Dirty filters cause insufficient airflow and can prevent the furnace from starting. Other reasons it won’t start can stem from improper thermostat settings, forgetting to turn on the gas line, or faulty pilot light.
Why does my furnace keep short cycling?
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.
Why does my furnace stop and then start again?
Typically, a normal-working system will switch on and operate until the set thermostat temperature is reached. It will switch off to allow the room to maintain the heat and only resumes when the temperature drops again. A furnace that turns on and off in quick succession means that it is short cycling.
Can a flame sensor be intermittent?
The flame sensor is a safety component that detects whether or not there is a flame in the combustion chamber. If this sensor is dirty, the dirt can cause the sensor to operate intermittently. When this happens, your furnace will most likely light, but because the sensor can’t properly detect if a flame is present.
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. This could be a relatively easy fix.
Can a bad thermostat cause a 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.
Why does my furnace stop working at night?
Short-cycling: If you notice the furnace shuts off regularly at night, it may be short-cycling. This happens when the furnace is too large for your home. If your furnace is short-cycling, it will turn on for a short period, then turn right off. This prevents it from heating your home properly.
How do I know if my thermostat is bad?
7 Ways to Tell Your Thermostat Is Broken
- Thermostat Has No Power. …
- AC or Furnace Won’t Turn On. …
- Heater or AC Won’t Turn Off. …
- Thermostat Doesn’t Match Room Temperature. …
- Thermostat Doesn’t Respond. …
- Short Cycling. …
- Thermostat Forgets Programmed Settings. …
- Thermostat Replacement Services.
Why does my furnace only run for a few seconds?
A common reason a furnace short cycles is because the heat exchanger, the part that heats your air, is getting too hot due to a lack of airflow. Once the heat exchanger overheats, it trips the high limit switch, which shuts the furnace down to protect it.
What are the symptoms of a bad flame sensor on a furnace?
6 Signs of a Malfunctioning Gas Furnace Flame Sensor
- Yellow Burner Flames. Open up or glance through the peephole of your gas furnace to see the color of the flames firing up in the burner. …
- Rusted Flue Lines. …
- High Utility Bills. …
- Water Leaks. …
- Old Age. …
- Constant Thermostat Adjustments.
How do you know if you have a bad flame sensor?
Signs of a bad flame sensor
Furnace burners turn on but go out after a few seconds. Soot and other debris is covering the end of the sensor (cleaning the flame sensor may fix this issue rather than a flame sensor replacement) Tip of flame sensor is black. Porcelain/sensor casing is cracked.
How much does it cost to replace a flame sensor?
Flame Sensor
It stops your furnace from letting off large amounts of natural gas if it’s not working properly. If the sensor is bad, it won’t be able to sense heat and will turn the furnace off. The average cost to repair or replace a flame sensor is between $75–$200.
How often do flame sensors need to be cleaned?
The service life of a furnace is 10 to 20 years on average. This means you’ll have to replace a flame sensor once, twice or three times over the course of the furnace’s life. Having a bad flame sensor is completely normal–you just need to know how to properly identify when it’s gone bad so you can replace it on time.
How long do furnace flame sensors last?
about 5 years
Note: According to HVAC.com, the expected lifespan of a flame sensor is about 5 years. Most furnaces last anywhere from 10 to 20 years. That means that you will have to replace a flame sensor 1x, 2x, or even 3x during a furnace’s lifespan.
How do I clean the flame sensor on my furnace?
Quote from Youtube video: So if you have a situation like this what you have 90% of the time is just a dirty flame sensor. So we'll go through the steps on how to clean it. So the right side of the furnace.
Where is furnace sensor located?
A furnace flame sensor is a very basic part of your furnace. It’s located on the burner assembly and is just a thin metallic rod. It’s usually bent, and it sits just in front of the pilot flame inside the furnace.
What causes a furnace flame sensor to get dirty?
It is a sensitive sensor so any type of dust or carbon buildup could cause it to malfunction. Most people have their furnaces in a basement or laundry area where there is excess dust in the air. This dust could stick to the sensor making it dirty and causing your furnace to shut down.
