What causes a weak flame on a furnace?
Your furnace has a limit switch that keeps it from running if the heat exchanger is too hot. Dirty filters, closed or blocked vents and other blockages in airflow are common causes of an overheated furnace. A bad limit switch. The limit switch may be bad and need to be replaced.
How long does a furnace flame sensor last?
If you’ve just replaced the sensor or had a new furnace installed, you can expect the flame sensor to last for about five years. The average lifespan of a furnace is 15 to 30 years, so you can anticipate a flame sensor replacement once or twice over the course of your homeownership.
What causes a weak flame on a furnace?
Your furnace has a limit switch that keeps it from running if the heat exchanger is too hot. Dirty filters, closed or blocked vents and other blockages in airflow are common causes of an overheated furnace. A bad limit switch. The limit switch may be bad and need to be replaced.
Why does my furnace ignite then go out?
A defective pressure switch could also be the problem with a furnace that won’t stay lit. This switch becomes active when it senses enough air flow to continue ignition. Therefore, if there isn’t adequate air flow, the switch won’t work, and the furnace will go out.
How long do heat sensors last?
If you’ve just replaced the sensor or had a new furnace installed, you can expect the flame sensor to last for about five years. The average lifespan of a furnace is 15 to 30 years, so you can anticipate a flame sensor replacement once or twice over the course of your homeownership.
How long does a heat exchanger last?
The heat exchanger is responsible for heating the air that circulates through your home in the winter. Heat exchangers usually last about 15 years. If you invest in maintenance, yours might even last 20.
How serious is a cracked heat exchanger?
A cracked heat exchanger poses a serious threat to the safety of your home. If there’s a crack in one of the cells of the heat exchanger, the gases being burned – carbon monoxide, sulfur dioxide, nitrous oxide – could leak into your home, causing illness or, in extreme cases, death.
Why is the furnace blowing cold air?
If your furnace is blowing cold air in your home, this is a sign of an issue with the flame detector, gas supply, air filter, pilot light, or condensate lines. Many of these issues are able to be easily solved on your own by sanitizing or replacing components in the gas furnace.
What happens if your heat exchanger is cracked?
A cracked heat exchanger poses a serious threat to the safety of your home. If there’s a crack in one of the cells of the heat exchanger, the gases being burned – carbon monoxide, sulfur dioxide, nitrous oxide – could leak into your home, causing illness or, in extreme cases, death.
What does a cracked heat exchanger flame look like?
The Furnace Flame Looks Yellow
However, if the furnace produces a yellow flame, it can mean that your burner is dirty or your heat exchanger has cracked. But if the flame is yellow and also flickers, the chances are high that there are more damages in the furnace.
What does a flame sensor look like on a gas furnace?
The flame sensor is a rather simple device located at the burner assembly. It’s not much more than a thin, usually bent, metallic rod that sits in front of the flame stream inside the furnace.
How much does it cost to replace a flame sensor on a furnace?
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 do you clean a dirty flame sensor?
Once you have removed the sensor, gently rub the metal rod (and nothing else) with a very light grit sandpaper. Remember, you’re not sanding down an auto body here, just ridding the sensor of any buildup. Then, use a clean paper towel to wipe clean any dust left behind by the sanding.
How often does a flame sensor 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.
Can you use sandpaper to clean flame sensor?
The sensor is part porcelain insulator with a 2 to 4” wire that extends above the burner. Remove it and sand it lightly with 150 grit sandpaper or so, (I used a sanding sponge), to remove all the dark carbon off the wire. Once it is clean, it should work for a month or two until you can order a new one.
How hot should air be coming out of vents gas furnace?
If everything is working properly, the air coming out of your furnace will be about 40° – 70° warmer than the air coming in; this increase is called the temp rise. If the temp rise is too high, it could be caused by an oversized furnace, undersized ductwork, a combustion problem, or an airflow obstruction.
What causes a cracked heat exchanger?
What is the cause of heat exchanger cracks? Overheating causes nearly all premature heat exchanger cracks. When a furnace cannot get enough airflow, the heat exchanger overheats and suffers excess stress from expansion and contraction. Over time, the heat stress causes cracks near weak areas such as bends or welds.
How long does a furnace last?
A well-maintained furnace can last at least 15 to 20 years, but completing annual maintenance and being diligent with repairs can extend its life even longer.
How do you clean a heat sensor?
Once you have removed the sensor, gently rub the metal rod (and nothing else) with a very light grit sandpaper. Remember, you’re not sanding down an auto body here, just ridding the sensor of any buildup. Then, use a clean paper towel to wipe clean any dust left behind by the sanding.