Flame sensor hello my problem is the same as others. My heater will ignite but will not stay lit once blower kicks in. Cleaning the flame sensor sounds like a good answer. but where is it located. thanks

where and when it make sound?

There is an ignitor and a flame sensor. If the ignitor does not ignite the gas after a time, it goes out. If the flame sensor does not detect ignition the gas valve closes. When you start it you should see the ignitor come on like a light bulb and glow, then the gas valve opens and you get ignition. Then the flame detector turns on when the ignitor goes out. Flame detectors are like a chrome wire that has one connection to it and it sits part of the way in a burner. They get dirty and corroded. When that happens it shuts down. You can clean the flame detector with steel wool of scotch brite pads. Dont get too carried away doing that though.

Dirty flame sonsor.Left side of the burner rack..A steel pin with white porcelin & 1 wire to it.remove the one screw(1/4"hex) holding the bracket and clean/polish the rod part with light sandpaper or steel wool.Re-install and the flame should" Prove" and stay lit.Thanks

,Hello, Make sure the flame sensor is clean near the burners, The flame sensor is a metal rod that is on the opposite side of the ignitor. To clean the flame sensor you will need some steel wool, turn off power to the furnace and remove the flame sensor and clean it with the steel wool. After cleaning reinstall it and turn power back on to furnace.

If this has an igniter could be flame sensor. Flame sensor tells gas valve that flame is present or it will kick out. Flame sensor should be small rod connected to one wire, and it is on the flame somewhere sometimes opposite end from igniter If you do have sensor turn power off remove sensor and clean If white film on it. I usually clean it with dollar bill

look for the flame sensor , its a small metal rod in front of one the burners you need to sand it with some sandpaper and it should stay lit. attached is a pic of what it looks like.

Sounds like it is not proving flame, to check you need a meter that will read DC microamps. without knowing the brand I can't say what you should be looking for. Trane furnaces need at least 1 DC microamp to prove presence of flame. Usually you will see 2 - 2.6 or so, but it depends on what the manufacturer specs to prove flame. At minimum you can pull the burners out and clean them really good (especially the cross-over wings) because if the flame doesn't roll down to the sensor fast enough during the trial for ignition it will recycle and eventually lockout. If it stays lit longer than 20 sec, it most likely is proving flame and cycling off on high limit because the blower is not coming on. The typical blower on delay is 45 sec from the time flame is proved to when the blower is energized

Could be the flame sensor is bad,it looks like a thermocouple scratch it with a knife then try again.

Clean the flame sensor with a piece of sand paper or a piece of emery.

Look at the sensor that tells unit that everything is lit. There should be some sort of sensor that tells the ECU that the ingnition area is a burn temp. It sounds like the unit can't tell that flame is lit. Hope this helps.