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When Thermostat is satisfied and shuts down the furnace, the furnace fan will not shut off. It is supposed to continue to run but only for a short time. This one will not shut off at all.

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Your thermostat has a feature for the fan AUTO or ON. If it is in the AUTO position and still won't shut down then I would check the Fan relay. Newer models have a control board with the relays built into them so the control board would be suspect. Older models use a Fan/limit. The limit has a probe in it. As the heater warms the bi-metal inside it twists around and the fan comes on at about 110f. When the thermostat is satisfied the burner shuts down but the fan still runs till the heater cools down the bi-metal cools off and shuts down that fan. These will hang up with age.

Posted on Nov 11, 2010

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I have new blower motor. it dosen't stop running


Could be a bad blower motor resistor,mounted by the blower.

Sep 28, 2016 | 2002 Dodge Ram Pickup 1500

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When thermostat turned up furnace ignites, heats and fan starts when plenum is up to temp. When thermostat is turned down flame goes off but fan continues to run.


If your furnace is relatively new, as in 10 years old or less, there should be a field adjustable 'cool down' cycle. On the circuit board there should be a dip switch or series of dip switches with 30, 60,90,120 indications. These numbers represent the length of time the relay on the circuit board allows the fan to run AFTER the thermostat satisfies. You may be able to adjust the time frame down one position from where its positioned now.


The second possibility, if the blower never shuts off at all is that the relay itself could be stuck in the closed position and keeping the fan on.

Sep 30, 2015 | Heating & Cooling

1 Answer

This is a propane furnace that continues to run even after being shut off and plenum cools. No chimmey just pvc pipe to exhaust outside. Does that help.


The fact that the plenum cools down suggests that the thermostat is satisfying its setpoint and correctly turning off the gas flow....but....if the blower is continuing to run after the plenum cools down, it indicates the blower relay on the control board is stuck in the closed position (if it is a newer style furnace) OR the "fan' portion of the 'fan-limit' control is stuck closed if it is an older furnace.

If it is a newer one with a circuit board, the board cannot be field serviced...it must be replaced. Some furnace nmanufacturers have a secondary board that controls the fan alone and is cheaper than the furnaces with the single 'control board' that performs all functions of the heating/blower sequence.

Unless you have a fair amount of understanding of electricity, you should at this point call a service company for service.

Sep 29, 2015 | Heating & Cooling

1 Answer

Why does furnace fan run continuously?


No on the thermosat go and check fan is not on the summer switch setting , if the fan is running it could be the AFC automatic fan control not shutting the fan off

Dec 29, 2012 | Honeywell Heating & Cooling

1 Answer

Robertshaw thermostat will not shut off heat


gas or electric furnace? sounds like bad sticking t-stat but could be sequencer or gas valve. The fan will continue to run if the unit is hot safety feature so the fact that the fan continues to run does not mean the t-stat is diffidently bad.

Mar 01, 2012 | Heating & Cooling

1 Answer

Furnace will not shut off after the setting is reached. have changed thermostat. Temperature reading goes down on thermostat, furnace still runs. Model : Goodman furnace,gmh95/gch9


Check if your thermostat is set on 'o fan' setting.
If it is, trey to set it on 'Auto-fan' instead.
since it seem as if the heating does go off,only the fan may be running continuously.
this is possible if the thermostat is incorrectly set or installed.
good luck.

Jan 30, 2010 | Goodman GMS90703BXA Heater

1 Answer

Fan continues to run after heating off


Hello, if you're fan continues to run after the t-stat is satisfied, I want to ask you, is this a gas furnace and maybe an older one? The reason for this, this is a common problem we have in the field with older units like the late 80's. If so, you will have on the furnace a fan control that inserts into the heat exchanger (fire box) to see what the temp. is. Under the cover it has a temp. dial with different heat settings on it that rotates with the heat and when it gets to a preset point, will turn on the fan. When the t-stat is satisfied, it will cool down with the fan still on until it gets to another preset temp. and shuts the fan off, or is supposed to. If you have this type, believe me this is sticking, worn and will need to be replaced. Now, to cover a newer furnace, the fan is controlled through the main control board and you have the automatic ignition. The board is faulty and will need to go. Please take my advice, and if you have any questions about the unit, or if I am wrong on the type that you have, please contact me so you and I can solve this for you. Best of Luck,
Shastalaker7

Nov 22, 2009 | Coleman Heating & Cooling

1 Answer

Furnace runs but once it gets to teamature it does not shut off but goes in and out of stages


Disconnect the thermostat wires from the circuit board. Tape door switch closed. Put a jumper on R and W on the circuit board. Let the heater run for about 5 min. Disconnect the jumper, furnace should shut down. If it continues to run you have a bad board. When you reconnect the thermostat, look for a shorted wire or a bad thermostat. I suspect a bad board if the furnace is hunting thru the stages.

Nov 03, 2009 | Goodman GMS90703BXA Heater

1 Answer

The fan runs all the time.


Disconnect your thermostat from the wall. If the fan shuts off then you probably have a bad or miswired thermostat.
If it continues to run, disconnect the thermostat wires from the furnace. If this shuts the fan off then you have a problem with the thermostat wires.
If the fan continues to run with the thermostat wires off of the furnace,
then you have a problem with the furnace.
Even though the fan stays on...... does the furnace still work? If so I bet you have a bad or stuck blower relay. If the furnace does not function other than the blower than you most likely have a safety control that is open. Worst case you could have a bad circuit board.
Good luck.....

Apr 10, 2009 | Honeywell Electronic Programmable...

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