Hello,

I have a Bryant gas furnace 383KAV that is 7 years old. Currently the burners come on and then go off after a few seconds. After this happens 4x the furnace delays for 3hours. I thought the flame sensor might be dirty - but I cleaned it some and nothing came off. That didn't help. Filter is OK. I checked voltage at flame sensor. It is ~10.8 volts cold and when burners come on it jumps around sometimes reaching 18 volts but it is not steady. Occasionally the burners will stay on and it operates normally, but the problem is rather consistent today.

Do I need a new flame sensor?
Is this just a thermistor to ground? Or is it a thermoswitch?

Thanks for your help.

Since you are playing the guessing game I would replace the ignitor first. If that does not work call for service because the rest of the parts are very expensive to guess at replacing.

Quote:

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Originally Posted by FixHondas

Hello,

I have a Bryant gas furnace 383KAV that is 7 years old. Currently the burners come on and then go off after a few seconds. After this happens 4x the furnace delays for 3hours. I thought the flame sensor might be dirty - but I cleaned it some and nothing came off. That didn't help. Filter is ok. I checked voltage at flame sensor. It is ~10.8 volts cold and when burners come on it jumps around sometimes reaching 18 volts but it is not steady. Occasionally the burners will stay on and it operates normally, but the problem is rather consistent today.

Do I need a new flame sensor?
Is this just a thermistor to ground? Or is it a thermoswitch?

Thanks for your help.

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I removed the flame sensor and used sandpaper on it. After reinstalling it, the furnace is working properly again.

When it stoops working again replace the sensor.

If the problem persists then try this:

The "Cross-overs" (Slots on the end of the burners) are clogged with dust or residue. So, remove the burners and clean them out. Be careful not to break the ignitor, you may just want to take it out before doing this. I had five burners in my furnace. The burners are the silver tubes where the flame comes out. I just flushed mine out with water and then dried them. Now, my burners light on the first try every time. This is easy to do and will most likely fix your problem.