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Heat on thermostat won't turn off when switched to the off position. Blower runs when heat is turned to the off position. The fan is on automatic.

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95% chance that the heat relay is stuck closed (on)

You can disconnect power, locate the heat relay, see if you have continuity between the two leads on the load side of the relay. (with the two wires off)
If you do, the relay is stuck. Sometimes you can lightly tap the relay and it will unstick, but chances are it will just stick again soon.

If the relay is stuck/sticking, it needs to be replaced.

They usually run anywhere from 6 to 26 bucks at the local HVAC supply house.

Posted on Dec 06, 2008

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2 Answers

Indoor blower won't shut off on heat pump


I would look to replace a relay that is not shutting off or replace the thermostat itself.

Nov 14, 2015 | Honeywell Air Conditioners

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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 | Air Conditioners

1 Answer

Auto fan does not start electric furnace


see this causes and fix it. God bless you
If the furnace won't run, check the electrical service panel for a blown fuse or tripped breaker. Also make sure the power switch on or near the furnace is turned on. Check the unit for a reset button and try it. Some units have a built-in breaker or fuse panel.
If there is not enough heat, raise the thermostat setting five degrees to see if it turns the unit on. If the unit still does not generate enough heat, check the comfort controls . Clean or replace a dirty filter, clean the blower assembly (see the Forced-Air Distribution Fix-It Guide), and make sure that all registers are open and not blocked.
If the furnace turns on and off repeatedly (cycles), clean or replace the filter; and clean the blower assembly (see Forced-Air Distribution Fix-It Guide).
If the furnace is noisy, make sure access panels are mounted and fastened securely; spray squeaking belts with fan-belt dressing and replace worn or damaged belts; adjust the blower belt; lubricate motor and blower oil ports.
If the element does not heat, refer to the Heating Element Fix-It Guide for guidance.

Oct 08, 2012 | Coleman Mobile Modular Home Electric...

1 Answer

When main switch to heater is turned on, only the flame comes on - no heat or blower. Have tried numerous times to reset by turning main switch off for five minutes, but still does not work. Any...


Does the fan come on when you turn the Fan to ON at the thermostate? If it does then it could be the blower board not turning the low speed blower tap on. Or the Fan & Limit switch not working. If the fan doesn't come on in the on position then the blower motor could be out or the run capacitor.
If the blower comes on it the ON position then you can run the heat with the fan in the ON position till you can get the heat relay looked at.

Dec 21, 2010 | Air Conditioners

1 Answer

We have a White-Rodgers 1F80-51. The fan blows


Usually when the furnace blower motor runs all the time
The limit switch or rollout switch is usually open or bad.
The furnace board is seeing that one of those switches is open, so it brings the blower on to try to get the heat out of the combustion chamber area, so the switch will close. But if the switch is bad and won’t close, the furnace board will keep the blower running continuously.

May 31, 2010 | Air Conditioners

1 Answer

I just changed the control board in my york furnace the old one shorted out upon putting the new one in it gives me the trouble code of the led blinking 9 times and the big blower runs continuously please...


On the back of the bottom door, is a led code which will tell you what could be wrong. I would turn power off, disconnect the thermostat wires, but unit back
together turn power on, blower should not run.

Next make sure fan switch at thermostat is not in the on position. Turn power off and put a jumper between
r and w. Turn power on the blower may come on and
then shut off, heat should come on and then blower
again. If this is true, then you have a problem with
the thermostat or thermostat wires, make sure these
wires are not touching

Feb 11, 2010 | Air Conditioners

1 Answer

I have an intertherm electric furnace FEH-A020, with multispeed blower installed when A/C added. My problem is blower operation. at the end of the cooling season with fan set to auto operation the fan ran...


The model of T-stat you gave comes up as a discontinued model on Honeywell's web site, but it looks to be a manual stat that type of stat would have to be wired with a summer winter switch with electric heat, allowing it to turn on the fan with a call for heat. If yours is a programmable T-stat you would need to select electric heat or in the installers set up change the default setting for fan from unit controls fan in heat to thermostat controls fan.

Oct 17, 2009 | Intertherm P3RA-048K Air Conditioner

2 Answers

The fan in the airhandler wont shut off.


The fan is controlled by a blower timer board located inside the air handler, or on older units it has a relay called (of all things) a blower relay. If these items were at fault I doubt removing the thermostat would cause the blower to go off. if bad causing this problem the blower would continue to run even with thermostat removed.

But it is also controlled by the thermostat.

You mentioned that if you remove the thermostat it cuts off. There are 2 switches on most thermostats.
1 has Cool, Off, Heat, and Emergency Heat (on a heat pump stat)
2 The other switch has On and auto (it is for the fan motor only)

I believe because it stops when you remove the thermostat that the switch on the fan is set to on possibly. It should be on auto-matic. This way the fan motor only come on with cooling or heating. If in the on it stays on all the time. If this is the case just switch to AUTO.

Or the thermostat may be wired wrong. The G terminal is where the fan motor gets instructions from the thermostat. Make sure its on G at the stat and the correct wire at the blower coil is being used for the corresponding wire going from the stat to the blower for G. Don't confues G for green it could be any color. The terminals are not for color but it makes more sence to make them color - letter identified. On the other end soemtimes the wires are not colored the same so look carefully.

Also a whisker of a thermostat wire could be touching inside the thermostat and causeing the motor to run 100%. Look carefully at this and see if it has too long of thermostat wires stickinhg on out under the screws to where they may tough other things.

If neither things stop or show the problem and it deffinately stops when thermostat is removed the thermostat is most likely bad.

If this helps you 1 way to make the repairs your\self or helps you realize you need a technician please rate mne as high as you can.

May 14, 2009 | Air Conditioners

2 Answers

My air handler comes on ,not the outside unit when my thermostat is in the off position even if i turn the thermostat down to 50 and have it turned off the air handler comes on for about 5 to 10 minutes...


If you have a standard thermostat the fan switch is for the air handler only. It completely over rides the thermostat for most settings. Now lets see this is what I'd expect:
fan switch on Indoor fan runs all time
Fan switch auto Indoor fan only runs when thermostat is set to cool or heat and the thermostat is turned up above room temp for heat or below room temp for cooling. In both of these modes the furnace blower comes on and stays on til the room temperature is satisfied. The outdoor unit only comes on for AC the out door unit will not come on for heat or the "on" setting on the thermostat. See exception 1 & 2 below...

Exception 1- (in a heat pump the out door unit runs in both heat and cool mode unless it has emergency heat turned on then it will not come on outside in the heat mode, and depending on the type of heat pump and furnace or air handler it is). A heat pump thermostat usually has "backup heat" and an "emergency heat" setting switch on the thermostat.
Exception 2 - On some thermostats they are made to cycle on the heat if the temperature reaches a preset temp (around 50'f usually but definitely by 40'f). This mode prevents freezing when if instance the homeowner is away or while the home is under construction. In this mode the fan inside can run but the heat usually comes on with it.
Exception3 - On some electric furnaces the heating strips may be individually controlled and thus not all come on at one time. This may give the feel of no heat especially if the room is cold.

Now there may be other exceptions but Ive tried to give you a heads up on some of the most common ones.
If you need more help please post more specifics about your unit/system as to for sure what switches are set to what setting and what is happening with each. My first though was that maybe your system is OK and you needed to know if the thermostat was working properly.

If this helpd you understand your problem would you please give me as hifgh a mark as you can. Thnaks for using fixya and good luck.

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1 Answer

Rheem heat pump. blower will not turn off


The fans are set to delay for 60-90 seconds to remove all heat from the heat exchanger/heater elements.

If the fan runs any longer than 3-4 minutes after the Emergency Heat shuts off, you may have a bad sequencing relay in the air handler.

Jan 27, 2009 | Air Conditioners

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