It’s Not Lined Up. The pilot light flame needs to completely envelop the top of the thermocouple rod so it knows the flame is on. If the thermocouple isn’t lined up correctly, it won’t read the flame, and will shut the valve for the gas.

When I release the pilot button the flame goes out?

If you’re able to light the pilot light, but it goes out when you release the control knob, the thermocouple probably needs replacing. The thermocouple is a safety device that shuts off gas flow if it senses the pilot light is out, but when damaged it loses its regulatory ability.

Why does my gas heater keep cutting out?





If your furnace keeps shutting off, it could be due to low airflow. There are several indirect issues that cause low airflow. Dirty Air Filters. If you don’t change your air filters often enough, the filters will become dirty and clogged, which means the heat exchanger retains heat and eventually causes it to overheat.

Why does my pilot keep going out on my gas heater?

If it senses that your water heater pilot light keeps going out, the thermocouple will shift off the gas supply to the heater. Over time, thermocouples can malfunction, accumulate dust buildup, or the device can get bent away from the pilot light’s flame.

Why does my furnace flame keeps going out?

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 the pilot keep going out?

Filthy Pilot Light Opening Can Make Pilot Light Keeps Going Out. If the mouth of the pilot is filled with gunk and dirt, it’s nearly impossible for it to hold a flame. The flame it does hold will be weak, and easily extinguishable. A dirty pilot orifice will prevent your pilot light from staying lit.

How do you clean a thermocouple on a gas heater?





Clean the thermocouple – using the emery cloth sandpaper, sand the ends of the thermocouple and then give it a finishing touch with the lint-free cloth. Hopefully, you can get to the ends of the thermocouple without having to detach it from the assembly, but you may have to do that.

Why does my heater turns off before reaching temperature?

A lack of airflow can cause your furnace to stop heating before reaching the set temperature. Ensure there is nothing impeding airflow around your furnace, within your furnace and through your ducts. Check that registers are open, no ducts are damaged or crushed and replace your furnace filter.

How do I stop my furnace from short cycling?


Quote from Youtube video: So to fix this issue shut off your thermostat. And open up the furnace. And then replace the batteries on the thermostat.

How do you clean a flame sensor?

Quote from the video:
Quote from Youtube video: As far as cleaning the sensor itself. There the factory recommended way of cleaning them is either with a piece of steel wool or actually scraping them with a straight edged knife.

How do you reset the flame sensor on a furnace?



Quote from the video:
Quote from Youtube video: And we're just going to sand this a little bit and we'll see if that solves our problem all right I used our Emery cloth and I remove the buildup from the flame on the thermocouple.

Where is the flame sensor on a gas furnace?

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.

How much does it cost to replace a furnace 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 long do furnace flame sensors last?



about five years

Flame sensor lifespan



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 do you test a flame sensor?

Quote from the video:
Quote from Youtube video: Then set your meter to measure. Microamps. As soon as the flame is established. You should see a microamp reading on your meter. My manual actually says i'm looking for between one and four microamps.

Why does my furnace keep starting and stopping?

This behavior is caused by something cutting short each furnace cycle since your furnace is being forced into a short cycle to keep your home the temperature set on your thermostat. A furnace that is sized properly for your home should start and stop 3-8 times in an hour.