Forced air heating or cooling air handler troubleshooting: what to chedk first if the air handler's blower fan won't shut off.

This article describes what to check if the furnace or forced air blower fan does not stop when you expect it to do so.

These same diagnostics also aid in air conditioning blower assembly diagnosis when an A/C blower continues running. We explain what switches or controls may be set improperly or what else, such as a shorted wire, can cause continuous HVAC fan operation.

What to Check if your Furnace Fan or Air Handler Blower Fan Runs Continuously

These diagnostic steps are for an air handler, blower, or furnace fan that just won't quit running.

Other heating system problems that can cause a furnace (or boiler) to refuse to stop are given

at HEAT WON'T TURN OFF.

First, confirm that the room thermostat is NOT calling for heating or cooling.

In the heating season, just set the thermostat(s) to the lowest setting and confirm that room temperature is above that point. In the cooling season do the opposite - set the thermostat to its highest setting and confirm that room temperature is below that point.

You have told the thermostat to turn off the HVAC equipment.

If the equipment was running give it three to four minutes to shut down.

Next: If the blower just keeps running no matter what, there are two places to check switch settings before calling your heating or air conditioning service company in response to a furnace fan or air conditioning fan that just keeps running without stopping:

1.CHECK the FAN-AUTO setting - At the room thermostat: the FAN-AUTO-OFF or FAN ON/OFF switch on the room thermostat should be checked.

The fan control should be set to AUTO. You can try turning the switch to OFF too.

Details of checking the thermostat's FAN-AUTO-OFF or FAN-ON switch position when the furnace (or air conditioning) fan won't stop running are

at FAN WONT STOP - THERMOSTAT SWITCH

Other snafus such as a shorted thermostat wire can also cause the A/C or warm air furnace fan to run continuously.

Those problems are explained

at THERMOSTAT WON'T TURN OFF.

2. CHECK for a MANUAL - ON Switch - At the furnace or air conditioner air handler or blower unit: the fan limit switch may include a switch that manually keeps the fan running.

We discuss this switch right here. If you don't know where to find the limit control switch on your furnace or air handler,

see FAN LIMIT SWITCH.

Some models of Fan Limit Controls such as the Honeywell L4046B229& Universal Fan and Limit Controler, in particular the Honeywell L4064B,W, and R models have a manual fan switch that overrides the fan control to keep the fan running continuously. The white knob and white arrow in our photo point to this manual fan switch.

Take a look at the fan limit control switch. Before pulling the cover off of the switch, just see if the switch includes a control such as the white push-pull switch like the white device shown at the lower left in our photo.

Depending on the position of this switch (pushed-in or pulled out) the fan may be on manual override - causing the fan motor to run continuously.

Check the printing on the switch face to see if you should push the switch in or pull it out to leave the blower on "Auto". ("Man" or "Manual" would be forcing the fan to run.)

Which way to set the manual furnace or air conditioner blower fan switch:

Usually: "Push-in" position on this (Honeywell) fan limit switch is for continuous fan operation and "Pull out" position is for automatic fan operation.

There are some reasons (explained

at BLOWER FAN CONTINUOUS OPERATION)

to leave the blower fan on continuously for long periods, such as to use an air filtering system to improve indoor air quality.

And in some buildings we may run the blower continuously for more even or better conditioned (heated or cooled) air distribution.

What Else to Check if the Blower or Furnace Fan Won't Stop

On the off chance that someone has inadvertently mis-connected or shorted fan control wires at the fan limit switch, also check

out FAN LIMIT SWITCH INSTALLATION & WIRING.

On the chance that there is a shorted thermostat wire, a problem that can also cause the A/C or warm air furnace fan to run continuously

see THERMOSTAT WON'T TURN OFF.

Details about the manual FAN ON or FAN AUTO ON switch right at the furnace or air handler at the manual

at BLOWER FAN CONTINUOUS OPERATION.

This article series answers most questions about central heating system troubleshooting, inspection, diagnosis, and repairs.

We describe how to inspect, troubleshoot and repair heating and air conditioning systems to inform home owners, buyers, and home inspectors of common heating system defects.

Contact us to suggest text changes and additions and, if you wish, to receive online listing and credit for that contribution.

What to Check if in Heat Mode the Furnace fan keeps running with no heat coming from the furnace

6 steps to getting heat on when the fan runs but the furnace does not

If the furnace does not even try to run, that is if it never even starts, then follow these steps:

1. Check the thermostat settings to be sure that you are calling for heat (set-temperature is above room temperature).
   
   See THERMOSTATS, HEATING / COOLING - home
2. Check that the thermostat FAN switch is set to AUTO not to ON.
   
   See THERMOSTAT SWITCHES, EXTERNAL
3. Check that the manual FAN ON switch at the fan limit switch in the furnace or air handler is not in manual ON position.
   
   See FAN LIMIT SWITCH for details.
4. Check the furnace primary controller to see if the "reset" button on the control (or on the burner motor) has popped out - you can try pressing the switch in ONCE but don't keep pressing it as doing so is unsafe.
   
   For oil fired furnaces see RESET SWITCH - HEAT CONTROL
   
   or see RESET SWITCH, CAD CELL RELAY
   
   or on older furnaces see STACK RELAY SWITCH
   
   For electric motor reset switches that are present on some (not all) oil burners
   
   see ELECTRIC MOTOR OVERLOAD RESET SWITCH
   
   For gas fired furnaces
   
   see FLUE GAS SPILL SWITCH TRIPPING & RESET; other defects such as a bad thermocouple can keep the gas burner from igniting or burning.
   
   For gas burner thermocouple problems
   
   see THERMOCOUPLE REPAIR / REPLACEMENT
5. Check for voltage at the oil burner primary control. This is a simple test to see that power is actually being delivered to the oil burner control. You can use a neon tester, a VOM, DMM, or a voltage detector stick.
   
   Watch out: if you are not expert in safe use of electrical test tools you could be electrocuted - killed. Call an expert.
   
   See VOLTS MEASUREMENT METHODS
6. Check for a bad primary control: If there is voltage to the primary control, no reset buttons are popped, and the thermostat is calling for heat (check that right at the primary control thermostat wires) then I suspect a bad primary control unit itself.
   
   At that point your heating service tech will perform her own tests and then if needed repair wiring or replace the furnace control.
   
   Oil heat: see CAD CELL RELAY SWITCH
   or
   Gas heat: see the gas furnace controls cited above at step 4.

If the furnace tries to start but cannot keep running then there is a different problem such as no fuel or an unsafe condition.

See DIAGNOSE & FIX HEATING PROBLEMS-FURNACE - home

A complete list of oil and gas fired furnace controls is

...

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Reader Q&A - also see RECOMMENDED ARTICLES & FAQs

Readers Ask Why the Furnace Fan Won't Stop Running

My furnace fan in my house won't turn off when my unit is off - On 2020-02-01 by Tab

Blower fan continuously running while heat off switches on heat and on auto no fire in the box fan still run - On 2019-11-15 by Jon tester

Sometimes my blower fan won’t shut off for a while. It will work for half the day and then the other half of the day it will not shut off.If I flip the breaker off and right back on the fans stays off until the next cycle. - On 2019-12-28 by Jamie

My Coleman electric furnace will not shut off i have to use the breaker to shut it off - On 2020-12-04 1 by keith

I have a Payne all in 1 blower condenser unit. My blower is staying on all the time. - On 2020-07-13 by Spiro

Blower motor on air conditioner will not shut down. I put in a new control board,that didn't work.put in a new contactor switch.that worked for 8 day's then stopped working.put in another contactor switch .the same. fan motor still runs constantly. - On 2020-03-04 by Forrest

Reply by (mod) - What to check first if the blower fan won't stop in Heat or Cool mode

Jamie and others

First, always check your room thermostat. Has it been satisfied?

That is, if in cooling mode the thermostat is calling for the cooling system to run until the room temperature drops to the set temperature on the thermostat.

Or in heating mode we have the same problem: the blower runs but the furnace or heater isn't bringing up the room temperature to the thermostat setting.

Is cool (in cooling mode) or warm (in heating mode) air being supplied at your air supply registers?

Other Things to Check

Check the thermostat settings to see if the fan switch is set to ON instead of AUTO

Check the fan limit control in your air handler/furnace to see if there is a manual FAN-ON switch that is pulled out to keep the fan running

Check for a defective fan limit control or fan relay control switch.

Check for shorted wires at a control board or at the thermostat.

Blower still not shutting off? Start by stepping through the Diagnostics given on the page above. Let me know what you find and then we'll go over what questions remain.

 

AC is cooling but blower fan won't stop when it should

my ac is cooling fine but the blower fan wont cut off when its time any suggestions - On 2011-06-26 by gene -

Reply by (mod)

See our repair diagnostic steps at these two articles

• BLOWER FAN WONT STOP - LIMIT SWITCH -
• BLOWER FAN WONT STOP - THERMOSTAT SWITCH

Question: Can blower be deliberately set to run constantly

2019/10/18 Henri Nseke

Can blower running constantly

Reply by (mod) - yes by setting a FAN-ON switch

See these articles for complete detail covering both deliberate running of the blower fan continuously OR accidental or malfunction (the fan doesn't turn off when it should)

• FAN ON AUTO MAN THERMOSTAT SWITCH
• FAN ON SWITCH ADDITION
• FURNACE FAN WONT STOP - the article above on this page
• FAN WONT STOP - THERMOSTAT SWITCH

Brand New HVAC blower fan motor keeps running, never stops

Hi looking for some technical help with our HVAC system. I just replaced the blower motor in our furnace and it is running constantly since the change. I’ve disconnected it from the thermostat to isolate the problem and it still fires up as soon as the power comes on and stays that way with or without the furnace engaged.

The furnace itself still turns on and off as normal so I don’t think it’s the furnace limit controller reading overheat or going bad. I suspect it could be a bad relay.

The thing that really confuses me is that every morning when I wake up it tends to be off and stays that way until triggered either by the thermostat, the fresh air exchange or even me cutting the power and turning it back on gets it going again. Then it stays running until the next morning again. - On 2020-12-05 by Nathang

Reply by (mod) -

Nathan

Let's start by asking you to review the causes of blower fan not stopping that are given in the article above on this page because that's more complete than if I try to make that up again in an off-the-cuff reply.

Please take a look and let me know what you think and let me know what questions remain.

Followup by Nathan

Thank you. I have looked through your article extensively and tested at each place that is applicable to my system. Though I very well could have missed things as I get lost in the different types of systems.
It is an electric heating system with a heat pump and furnace.

1. Thermostat fan set to auto. Still runs all the time. Smart thermostat indicates that fan is off. Thermostat still calls for the fan when the furnace kicks on but when the furnace turns off and the fan is no longer called for at the thermostat it still runs.

2. It doesn’t seem as though there is a shorted wire as when I disconnect the thermostat from the furnace by disconnecting it’s wires at the Air Handler, the fan still runs.

3. There is no fan limit switch that I am aware of. It is a Trane and the furnace is BAY96X141502.

4. This system has a snap disk type limit switch. But I have checked it with a multimeter and it appears to be working correctly. Also the furnace is running as it should, just with constant blowing so if i understand correctly the limit switch would also be keeping the furnace from running normally.

Let me know if i’m missing checking something and I’ll check it out.

Reply by (mod) - Trane air handler using snap-disc & control board for fan limit controls

Nathan

Good going on those diagnostic steps.

You're right that a furnace that uses "snap disc" controllers to manage the fan won't have a Honewyell dial-type fan limit control; but it's of course still performing those functions: fan ON OFF and HIGH limit settings are controlled by those snap-disc controls (whose wiring you may want to follow & check out)

With the thermostat wires completely disconnected at the air handler end, and when the fan won't stop, we rule out an issue with shorted TT wires as well as a bad thermostat or thermostat setting.

Of course "won't stop" bears some clarification: it is proper for the fan to continue running for a minute or so after a call for heat, to extract the remaining heat from the heat exchanger and thus avoid damaging it.

If you are absolutely certain that there is no FAN ON control anywhere on the furnace, and it's disconnected from the thermostat wires at the furnace end then there's not much left: I'd suspect a bad snap disc, (I hear that you tested it), a shorted wire in the air handler, or a bad relay in the air handler.

In Heating Mode my ADP Air Handler (w/ hot water heating coil & a cooling coil) pump won't stop running

I have an ADP air handler with a hot water heating coil and a refrigerant coil. My thermostat controls the HW recirc pump.

In heating mode after the recirc pump shuts off the fan keeps running, forever.

I do not see an aquastat or fan limit switch in the housing anywhere.
my question is what controls the fan on/off? Is it programmed right into the circuit board or am i missing something?
thanks - On 2020-11-13 by ovsa

Reply by (mod) - ADP Air Handler with heating/cooling coils: fan control

Ovsa

There is usually a fan limit control in the air handler that turns the fan on or off depending on air temperature sensed in the plenum just above the heater's heat exchanger.

If the fan won't stop on your unit look for one of the controls described above on this page and that can be used to manually turn the fan on for continuous operation. One of those is on the fan limit control, another is often on your room thermostat, and on occasion there may be a fan control right on the printed circuit board in the air handler.

Look furhter for a control board failure: if your air handler does not use a separate timer-containing fan limit control the time delay in fan shut-off may be controlled by dip switches on a control board or by a hard-wired timer.

If you don't have the manual for your unit see

ADP ADVANCED DISTRIBUTOR PROUCTS heating & cooling systems

Or this may be the IO Manual for your unit:

ADP B-Series Multi-Position & Hydronic Air Handlers IO Manual [PDF] (2017) Electric or Hot Water Heat, with available Variable-Speed High Efficiency ECM Motor

Follow-up by ovsa

Thanks.
I looked all through the duct work and there is defintely no controller in there. The stat is set at auto and it is a fairly new stat.
The manufactures data says,

"Time delay for blower activation: 60 seconds (std.)

130 deg. F Aquastat (w/optional aquastat).

So i think that 60 sec delay is just built into the board

I don't see any options or markings for time delay nor any DIP switches.
Anyway I can test it?

thanks for your help

Found a bit more info looking through the data sheets,

Units without Factory Installed Aquastats or Deactivated Aquastats- A time delay of 60 seconds follows before the circuit between R and G are complete activating the indoor blower motor. The Air Handler fan will turn off 30 seconds after the Thermostat stops calling for heating.

Reply by (mod) - important for the blower fan to continue running for a brief time after the thermostat stops calling for heat

thank you for that it, too. Your paragraph yes I agree and we discussed in this article series The observation that it's absolutely important for the blower fan to continue running for at least a brief time after the thermostat stops calling for heat.

That's to extract the remaining heat out of a heat exchanger and thereby to avoid cracking the heat exchanger from high temperatures which in turn could make the furnace Unsafe and risk carbon monoxide poisoning.

So to be clear we should distinguish between the fan continuing to run for a brief interval typically 30 seconds or a minute after the call for heat of satisfied as distinct from the fan that just runs continuously.

If the fan runs continuously with never shutting off that's the situation discussed on this page and is not that he's purging cycle that you found in the instructions and that we also discussed in this article series

No Manual Switch on our Honeywell Fan Limit Switch: Should we Keep our Thermostat Fan switch set to AUTO?

If our Honeywell fan limit switch does not have the auto/manual push/pull button for the fan, then is it safe to assume that it is always set for auto? Our limit switch does not have the hole for the button in the cover, but when opened, it looks like the image above except there is no white button.

Maybe it broke off? (we just bought the house and moved in so don't know).

I read another comment from someone who said that not all models have the button, but our's keeps running well after the temperature is reached.

Any ideas on how to make sure the fan limit switch is set to auto? - On 2020-10-19 by Ed

On 2020-10-19 - by (mod) - yes

Ed

Essentially, yes. IF your limit switch has no MAN-ON switch (found as a white push-pull knob or as a small metal slide left-right lever) then yeah that control is in automatic mode.

However some thermostats also include a FAN ON / AUTO / switch that can also control the fan. I'm showing that in the thermostat switch photo just above.

If your fan NEVER turns off regardless of the thermostat setting then I suspect either one of the problems listed above on this page

OR

one of the situations described at FAN WONT STOP - THERMOSTAT SWITCH

In Cooling Mode & Fan on Auto every morning the fan comes on for a long time - why?

Hello! My Honeywell digital thermostat is set on cooling currently and the fan is set on auto. Everything seems to be working fine, except every morning the blower fan comes on for a long time (an hour or more) even though the thermostat shows no activity (cooling ihas not come on)

The inside temp is already at set point and drops to a couple degrees below the set point within a few minutes of the fan coming on and stays there the whole time the fan is running. This does not seem to happen at other times of day. The thermostat seems to be working the way it should. - On 2020-07-15 by Pam -

Reply by (mod): examples of normal long "ON" cycles in cooling mode

I'm guessing that your thermostat is using a night time setback that drops the call for cooling - an energy savings measure - OR it's simply that where you live the outdoor temperatures drop enough at night that your A/C system can stop running for a time.

Then in the morning when either your thermostat calls for cooling the home to a lower temperature OR when your house starts to heat up from first sun exposure the system turns on and has a longer run cycle to get the house temperature down to the cool setting.

That is, if the system is able to cool your home adequately through the hottest parts of the day it's probably operating normally.

Sometimes my Amana/Goodman ARUF Air Handler Blower just keeps going AFTER the thermostat is satisfied.

I've got the same problem, as posted On 2020-03-04 by Forrest.

My Amana/Goodman ARUF3714C airhandler keeps blowing, even after thermostat reaches set-point; compressor shuts down, but airhandler keeps blowing. The problem is *intermittent*--sometimes airhandler shuts off, sometimes it just runs and runs (not the 65-second efficiency delay).

Figured it was the blower delay relay board; replaced it and all seemed ok for a few days. It started up again today. I called Goodman and a tech suggested the thermostat might be defective. I had a new-in-box thermostat on hand, and wired it in.

It's doing same thing--seemingly random failure of airhandler to shut down, after reaching set-point temp.

I'm wondering about either the control wiring, or the 24 volt transformer. We had a power outage a few days before this trouble started, and wonder if the transformer might have been zapped, and isn't putting out 24 VDC.

The other possibility is wiring--if there's some random short or open, responding to equipment vibration or...?

How to check the control wiring? Is "C"/blue the common ground? What wires should be 'shorted' to each other, or to ground, during different operating states? - \2020-07-10 by Steve -

Reply by (mod) - If blower keeps running check to see if the thermostat has been satisfied

Have you tried disconnecting the thermostat right at the air handler? That can rule the thermostat out.

Then before replacing any other parts, check each of the controls.

When the air handler keeps running, the most-common cause is that the room has not been cooled down to the thermostat's set temperature.

So let's check for causes of that trouble, such as refrigerant loss or a compressor that is shutting down.

Followup by Steve

I've already disconnected the thermostat, and replaced it with a brand new one...along with replacing the blower time delay relay board.

Reply by by (mod) -

I got that, Steve, but I'm not clear on whether or not you found that by disconnecting the TT right at the air handler was done at a time when the AHU was running when you think it should not.

Taking that step not only rules out a bad thermostat but also mistakes in thermostat wiring and also the more-subtle problem of thermostat wires that are shorted together somewhere enroute.

Followup by Steve (in GA)

thank you, I shall ohm out the control wires from thermostate mount plate, and check for shorts. Assumption: the W, Y and G should have no continuity
to C (ground), or to each other--correct?

I found a discussion in another forum with same symptoms (intermittent failure of airhandler to stop blowing after reaching setpoint temp), where poster found the G line was left 'floating' (as opposed to being grounded) at setpoint shutdown. He conjectured about putting a pull-down resistor across G and C, to bleed any stray/leftover voltage at setpoint shutdown. He mentioned a 5K.

I just installed a 100K across G and C. Should only load 24VAC transformer with an additional 24mA.

A cooling cycle just completed--system cooled to setpoint, thermostat clicked, and about a minute later, airhandler stopped blowing---good! Fingers crossed that this solved it!

Reply by by (mod) -

Right.

The simplest and most straightforward test is to disconnect a thermostat wires at both ends and then working from each end test for any continuity between any pair of them.

Let me know what you find

Followup by Steve (in GA) - Clogged condensate drain causes intermittent shut down of the A/C system

Well, it turned out to be something verrrrrrrrry simple, but somewhat elusive!

I checked all wiring from tstat to airhandler, and from airhandler to compressor. All lines were continuous, with no shorts to any other lines.

The compressor continued to run intermittently, with no icing seen on coils.

The vent temps were65-66 degrees.

After everything I tried (new airhandler fan delay/relay board, NOS tstat) got same intermittent results, I figured the compressor was shutting down for some type of overheat situation.

The reality...was different....*facepalm*

Contractor came out, gauged compressor and looked at boards on compressor.

He then checked the airhandler, and the condensate float switch (here it comes!).

He saw some water in the switch cup, and said "you've got a clogged drainline. That's what's shutting down the compressor." He blew out the line, and systems been running like a top since then.

The clog must have been *partial*, with slow drainage. Between cycles, the line would drain enough to let float switch drop, and enable the compressor to run.

The compressor would run, cool the coils, and condensate would begin accumulating-- until it began to back up in the slow drain, and lift the float switch--and shut down the compressor. I did actually peek in the float switch cup several times, and never saw anything. I must have been looking after it had drained down.

Heat Pump Blower Fan No Lonter Runs in High Speed

Why won't the blower turn on high on my Goodman heat pump and Goodman furnace while in the cooling mode - On 2020-05-23 by Anonymous

Reply by (mod) -

If the blower previously would run in high speed AND if nobody has changed any of the DIP switches on the blower control board, then I suspect a failed relay or control board.

Genteq Endura ECM Blower Fan Runs Constantly - Why?

Thank you for all the very very helpful information found on this website! I am a new homeowner and I found the blower fan (Genteq Endura ECM FM19, 1/2 hp, 230VAC) installed has been running constantly. This is what I have gathered so far:

1. if I disconnect 5-pin low voltage signaling on the ECM, the fan still runs.

2. I checked voltage on the 4-pin power supply to the ECM, they are all correct (C-0V, L-115V, G-0V, N-115V).

3. snap-disc thermo switch checked.

4. heat sequencer checked (I have a heat pump and electric heat).

5. fan relay is quite hard to reach, but when I call fan-on, the relay clicks and the fan blows a little bit stronger.

6. interior of ECM looks great, no dust, no rust, no busted capacitor, perfect rubbery seal.

I suspect the ECM module is programed to run the motor non-stop, by the builder or previous owner? Program # 604253-05. Or what else could be the problem here? Thank you again!

Regards,
Nemo - On 2019-12-04 by Nemo -

Reply by (mod) -

I agree with you that typically there's either a switch set somewhere or a shorted wire or bad control

Is my HVAC blower problem a bad ECM?

Thank you for getting back to me. You mean you think it's the ECM problem (bad or set that way) as well?

What do I need to do, if I don't want the fan constant blowing? - On 2019-12-04 by Nemo -

Reply by (mod) - Check dip switches or jumpers on fan controller

First let's identify the exact brand and model of heater and then look at the manual to see what settings are available.

On most equipment there's actually a user operable switch that will turn the fan to run continuously. But on some it might be a dip switch or jumper.

The other place to look of course is at the thermostat. You can rule out the thermostat by disconnecting the thermostat wires entirely at the heater. If the fan keeps running then it's not a thermostat setting.

Question: worried that my furnace keeps igniting - possible fire hazard

I think my air off and the fan off but my furnace keeps lighting up. I’m worried it with catch fire. - 2019/11/04 Misty Lawhon

Reply by mod:

Misty

I can't tell what's happening with your furnace from your brief text: is the thermostat calling for heat?

Watch out: In any event if you have the slightest worry that the heater is unsafe then

I hope you simply shut down the system then called for repair;

 

Question: why does my Air Conditioning air go through the heating furnace?

Why does the ac blow thru furnace - 2019/08/15 Rick

Reply:

It's using the indoor furnace blower fan to blow cool air through the same duct system used for warm air heating.

 

Thank you back to our readers for their generous comments

Thank you for all the very very helpful information found on this website! - On 2019-12-04 by Nemo

...

Continue reading at FAN WONT STOP - THERMOSTAT SWITCH, or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

Or see FURNACE FAN WONT STOP FAQs - questions & answers about why the furnace blower fan won't stop running

Or see these

Recommended Articles

• AIR HANDLER / BLOWER UNITS - home
• BLOWER FAN OPERATION & TESTING
• FAN, AIR HANDLER BLOWER UNIT
• FAN MOTOR START CAPACITORS
• FAN, COMPRESSOR / CONDENSER UNIT
• FAN ENERGY INDEX FEI
• FAN LIMIT SWITCH
• FAN LIMIT CONTROL SETTINGS
• FAN LIMIT SWITCH INSTALLATION & WIRING
• FAN LIMIT SWITCH TROUBLESHOOTING
• FAN RUNS ONLY ON FAN-ON / MAN
• FAN WONT STOP - LIMIT SWITCH
• FAN WONT STOP - THERMOSTAT SWITCH
• FURNACE BLOWS COLD AIR
• FURNACE FAN CYCLES AFTER HEAT
• FURNACE FAN CYCLES DURING HEAT
• FURNACE FAN STOPS EARLY
• FURNACE FAN WONT START
• FURNACE FAN WONT STOP
• WOOD FURNACE FAN LIMIT CONTROL
• FAN MOTOR START CAPACITORS
• FAN NOISES, HVAC
• FAN ON AUTO MAN THERMOSTAT SWITCH
• FAN ON SWITCH ADDITION
• FAN WONT STOP - THERMOSTAT SWITCH
• UNDERSIZED RETURN DUCTS - not enough return air

Suggested citation for this web page

FURNACE FAN WONT STOP at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

Or see this

INDEX to RELATED ARTICLES: ARTICLE INDEX to HEATING FURNACES

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