I have a rheem criterion II funace about 13 years old. After the furnace heats houst the gas and flame shut down but the fan continues to run until I manually shut down at thermastat. Which part do I need to order?

How long has the fan run before you shut it down at thermostat? What are you turning off at thermostat? (from heat to off). Can't tell you what part to order without knowing exactly what is causing the problem. Please a more detailed description of furnace operation.

The fan will run forever unless I shut it off. I am shutting it off at the thermostat from heat to off. It will bring it up to temperature OK but the flame goes off and fan continues to run.
Thanks for your input

Be positive that the tstat is set on auto instead of fan only,, not saying it is but I had a service call just the other day and that was all that was wrong

When you turn the thermostat back to heat, does the fan come back on instantly? Or does it wait until after the flame has started?

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Originally Posted by wmproop

be positive that the tstat is set on auto instead of fan only,,,not saying it is but I had a service call just the other day and that was all that was wrong

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I agree with wmproop, but if it were set on (fan on) then when you switch the stat to off, the blower would still run. Separate setting for heat, cool, off, and fan auto, on. They are saying that the fan will stop when they switch it to off, (in the heat cool off switch). Makes me think there may be a problem with the stat. Do you have a heat cool stat, or just a heat stat.

I have a heat cool stat. I was told it might be the sequencer. Expensive!! I have tried heat only and the auto setting and the fan still does not shut off. Thanks for the help

The fan waits until the flame comes on.

When you say sequencer(makes me think of electric furnace) do you mean the furnace control board? Try giving the baord a few good taps and see if fan doesn't shut off. This now definitely sounds like a baord problem. If you tap it after the fan has been running for at least two minutes, and the fan shuts off, you will need a new board. Parts on the baord are not replacable(wish they were). You would have to replace whole board if the problem lies there. This is definatley an interesting problem you are having.

May try this. Unhook the thermostat wires at the board in the furnace. Remember where they go so you can hook them back up correctly. Once they are all disconnected, take a piece of wire and jump the are and w terminal on the baord. Leave it jumped until flame has come on and wait until blower comes on. Once the blower has come on, disconnect the jumper wire and see if the blower shuts down within two minutes. Let me know what you find.

It is a gas furnace.

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Originally Posted by gerrytoolman

it is a gas furnace.

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I realize that. Sorry I wasn't more clear. You have already expained that you have a gas furnace. I just am not familiar with the term'sequencer' on gas furnaces. Usually see them in electric furnaces. I guess my question was,, what are you referring as a sequencer on the furnace(control board:?) Maybe a relay? Sequencers usually aren't very expensive in the whole scheme of things. Control boards on the other hand can cost a little more than you like to hear.