If I place … Other Products. Maybe you finally bit the bullet and turned your air conditioner on, or maybe you’ve been running your AC for weeks now. He then Central air conditioners are a convenient and economical way to cool down an entire house. The thermostat is what tells these separate systems to work together. And in some buildings we may run the blower continuously for more even or better conditioned (heated or cooled) air distribution. Contact us to suggest text changes and additions and, if you wish, to receive online listing and credit for that contribution. The clog must have been *partial*, with slow drainage. 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. Your Account. The second common call is exactly the opposite problem — what if the HVAC fan won’t turn off? If you have an air conditioning unit and the outside condensing fan does not shut off, there is a few common things to look for.. 3 Most Common Reasons Condensing Fan Motor Does Not Shut Off. With the thermostat off and the fan set to auto. Blower Won't Work on Central Air. Then, get the parts you need fast. The thermostat seems to be working the way it should. These problems are not easy DIY repairs and should be left to an HVAC professional. In normal operation, when your thermostat is set to "auto," it will tell the blower fan plus the heating or cooling components to turn on and off at the same time when the desired temperature is reached. BUTIt will "TURN OFF" the outside fan IF it is switched to "OFF position MANUALLY. The fan will run but it won't put out the air. Air conditioner won't turn off? If all looks good, check your home’s electrical wiring for a tripped circuit breaker or blown fuse. What wires should be 'shorted' to each other, or to ground, during different operating states? This article series answers most questions about central heating system troubleshooting, inspection, diagnosis, and repairs. one of the situations described at FAN WONT STOP - THERMOSTAT SWITCH. Tab Your heating service tech may find a bad switch or control or even a thermostat set wrong or shorted thermostat wires. On the off chance that someone has inadvertently mis-connected or shorted fan control wires at the fan limit switch, also check. It won't shut off until it hits 75.0 or 74.9 where it might say "74". dometic ac; holiday rambler; Recommended Posts. When your HVAC blower never stops running, your first stop is the thermostat. Common solutions for: My AC Won't Turn Off 01 - Condenser Coils are Dirty The condenser coils dissipate the heat as the refrigerant passes through the coils. That's My AC started acting up last night. 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. The vent temps were65-66 degrees. Examine the external wiring and make sure it’s all intact — sometimes, animals can chew on wires and cause damage to your unit. 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. This system has a snap disk type limit switch. If your furnace fan won’t turn off, you most likely have one of these 3 problems: Your furnace fan limit switch is set to “manual override”. 1. Verify the switch on the thermostat is set to “Fan” or “Cool” and make sure the air conditioner is turned on. Central home air conditioner service systems consist of two major components: a condensing unit that sits outside your house, and the evaporator coil (often referred to as an A-coil) that sits in the plenum of your furnace or air handler. I pulled out the battery & removed it from the wall. to leave the blower fan on continuously for long periods, such as to use an air filtering system to improve indoor air quality. "Use our quick navigation below to find the problem with your air conditioner" Do You Need an Air Conditioner Professional if Your AC Won't Turn On? This will cause the fan to blow chilly air into your home. 1. Had a Tec come out twice and still can’t figure out the problem. This does not seem to happen at other times of day. The compressor would run, cool the coils, and condensate would begin accumulating-- I can't turn off the honeywell thermostat fan. until it began to back up in the slow drain, and lift the float switch--and shut down the AND, my problem is: My outdoor fan doesn't stop! But as the air continues to cool the thermostat after it shuts off then it might even read 73. A/C unit fan won't shut off We noticed last week that the fan on our a/c wasn't turning off when the inside air had shut off. A. Ant5. Please look through those steps and let me know what you find. It's doing same thing--seemingly random failure of airhandler to shut down, after reaching set-point temp. You may be able to save yourself some money and fix the problem yourself! If you have a central AC unit, you should first look at your thermostat and make sure it’s set to “cool” mode. Check the temperature that has been set on the thermostat. 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. enough to let float switch drop, and enable the compressor to run. Is it programmed right into the circuit board or am i missing something? Let me know if i’m missing checking something and I’ll check it out. Your blower fan is what pulls the uncomfortable air out of your home, sends it through the air conditioner or furnace, and then distributes it back into your home. See DIAGNOSE & FIX HEATING PROBLEMS-FURNACE - home, A complete list of oil and gas fired furnace controls is, On 2020-12-05 - by (mod) - Trane air handler using snap-disc & control board for fan limit controls. Outdoor unit won't shut off unless I use the circuit breaker: This happens occasionally. I’m worried it with catch fire. Before calling your service technician out to start replacing components, check the thermostat settings first. Your Account. Test the contactor with a multimeter to see if it works. Check the contactor relay switch. If the fan continues to run, there could be a problem in the thermostat or the wiring. Sometimes my blower fan won’t shut off for a while. Laura 1 year ago Reply. The only other time your blower fan should be running on its own is if you've flipped the thermostat switch to "on" to temporarily run your blower fan for increased air circulation. Find your local office: See what services and offers are available in your area. This controls the low voltage supply. Having a central air problem. If the blower previously would run in high speed then I suspect a failed relay or control board. Extreme Temperatures: If it's extremely hot or cold outside, your HVAC system may not be powerful enough to reach your desired temperature. However some thermostats also include a FAN ON / AUTO / switch that can also control the fan. My Honeywell digital thermostat is set on cooling currently and the fan is set on auto. Problem: You are running your air conditioner and even when your system cools to the set temperature, the outdoor unit continues to run and just won’t shut off.The indoor unit may freeze up into a solid block of ice. When the home’s thermostat detects that the living space is warmer than its programmed temperature level, a cooling cycle begins. 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. I do not see an aquastat or fan limit switch in the housing anywhere. Let's start I 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. It is a Trane and the furnace is BAY96X141502. Trying to fix electrical problems on your own could cause more damage or even create a fire hazard. anything. Unfortunately, you’ll need a professional to fix those last 2 problems. see FAN LIMIT SWITCH. Check the air filter and evaporator coil for dirt and debris. Similarly, if a fan won’t turn when the power is on but will rotate freely when shut off it could be the sign of a bad motor bearing. The best way to check if your thermostat is responsible for the AC not turning off is to set it to room temperature or slightly above. Let me know what you find. Nathan If the fan doesn’t start running, you may have a bad fan motor. Return any part for 365 days. I have a 15 sheer unit that blows strong and then weak, but continues to go up and down when activated at Temp setting. Before calling the friendly HVAC experts at Howard Air, here are a few tricks you can use to solve some of the most common issues we see every season for heaters not turning off. We had a power outage a few days before this Blower motor won't turn off [ 3 Answers ] I have a Carrier central air and furnace model 28GS 036 000. She might check the diagnostics above on this page first. He blew out the line, and systems been running 2. How your fan normally works. Try the search box just below, or if you prefer, post a question or comment in the Comments box below and we will respond promptly. Well, it turned out to be something verrrrrrrrry simple, but somewhat elusive! 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. Well, if you are going to have a problem with your heating or air conditioning system, this is the one to have! 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. by (mod) You have told the thermostat to turn off the HVAC equipment. If you have difficulty getting the blades to turn, there may be debris wrapped around the fan axle, or the motor bearings may be dirty or jammed. If the thermostat won’t turn off AC, chances are there’s another problem that needs to be resolved. Figured it was the blower delay relay board; replaced it and all seemed ok for a few days. 2. However, over time the bearings in the fan motor can give out (usually making a screeching sound) or the fan belt can wear out, causing a squealing noise. I hope you simply shut down the system then called for repair; It's using the indoor furnace fan to blow cool air through the same duct system used for warm air heating. 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. - my furnace will not shut off i have to use the breaker to shut it off. Have you tried disconnecting the thermostat right at the air handler? Thermostat Settings: Check to see if your thermostat has been flipped to "on" instead of "auto.". Depending on the fuel (oil, gas, electric) you'll find different diagnostic routines in the ARTICLE INDEX given in the Continue Reading section of this page, Blower fan continuously running while heat off switches on heat and on auto no fire in the box fan still runs. Also, if the fan limit switch override (a small knob on the switch) somehow got set to MANUAL instead of AUTO, the blower will run constantly—whether or not your furnace is going through a heating cycle. posted 2010-Mar-27, 5:48 pm AEST O.P. In some cases, you can give the fan a ‘kick start’ by pushing it with a stick and if this occurs there is likely an issue with the capacitor. Use our DIY troubleshooting & videos. my central air conditioner won't shut off when temperature is reached why.? Thank you again!Regards, Nemo, This sounds as if the FAN ON switch is set to ON at the thermostat or on the fan limit controller inside the furnace air handlerANDthat your furnace is not working - that is the burner won't run. blower motor on air conditioner will not shut down. 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. But I have checked it with a multimeter and it appears to be working correctly. 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. Click to Show or Hide Citations & References, important for the blower fan to continue running for a brief time after the thermostat stops calling for heat, ADP B-Series Multi-Position & Hydronic Air Handlers IO Manual, HOME INSPECTION EDUCATION COURESES (Canada), HOME INSPECTION EDUCATION: HOME STUDY COURSES, Our recommended books about building & mechanical systems design, inspection, problem diagnosis, and repair, and about indoor environment and IAQ testing, diagnosis, and cleanup are at the. Turn it to fan "ON" to see if fan turns on. Archive View Return to standard view. or the refrigerant line could be damaged. My furnace fan in my house won't turn off when my unit is off. Furthermore, once the stress on your system becomes too much, you may find yourself with no heating or cooling at all. Your air conditioner won’t turn on. If the fan keeps running then it's not a thermostat setting. 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. What do I need to do, if I don't want the fan constant blowing? If there is a problem with the relay board, it might provide continuous voltage to the compressor. In many systems, the blower fan runs a minute or so before heating or cooling begins and ends to get air flowing. You mean you think it's the ECM problem (bad or set that way) as well? It is an American Standard 5000. When the home’s thermostat detects that the living space is warmer than its programmed temperature level, a cooling cycle begins. Modern window air conditioners often use an Electronic Control Board, sometimes referred to as the PCB, to control the functions of the individual components of the unit. Call us anytime 24/7/365. 4. heat sequencer checked (I have a heat pump and electric heat). Either way, to your surprise, something is not quite right. These problems are not easy DIY repairs and should be left to an HVAC professional. 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, On 2020-11-13 En español Live Chat online. We discuss this switch right here. There’s a problem in your thermostat wiring. 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. Thank you for all the very very helpful information found on this website! Location of Your Thermostat . Some condensers have an on/off switch and some just have a kill switch to shut everything down totally for maintenance purposes. trouble started, and wonder if the transformer might have been zapped, and isn't putting out 24 VDC. The fan will not shut off even when the thermostat 3-way switch (Cool-Off-Heat) controller is in the "OFF" position. A compressor that shakes or stutters when it’s turned on, otherwise known as hard starting. After everything I tried (new airhandler fan delay/relay board, NOS tstat) got same Although your fan never shuts off, your heating and air conditioning still works fine. Last night I turned the A/C off at the tstat and the compressor outside turned off, but the blower fan on my furnace kept going. Fingers crossed that this solved it! 6. interior of ECM looks great, no dust, no rust, no busted capacitor, perfect rubbery seal. Contactor problems can result in your central air conditioner fan not working. Turn off the A/C and set the fan to run (usually “auto”) on your thermostat to melt the ice around the coil. Your blower fan works together with your heating and cooling units, but it's really a separate electrical system. Outdoor unit won't shut off unless I use the circuit breaker: This happens occasionally. While the cover is off, oil the motor on older air conditioners. Let’s review some of the reasons why your central air conditioner turns on and off repeatedly so you or a trained technician can address the issue successfully. First let's identify the exact brand and model of heater and then look at the manual to see what settings are available. Most likely there is a bad blower relay on the board and boards can't be repaired. Air conditioner won't turn off? FURNACE FAN WONT STOP at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice. The sequencer is a relay (switch) that controls the heating element(s), they get stuck on and then the high heat limit won't turn them off even if the fan isn't running. I suspect the ECM module is programed to run the motor non-stop, by the builder or previous owner? 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. 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Ac systems the breaker to shut everything down totally for maintenance purposes ``. Furnace while in the heating mode ( if it is switched to `` on '' instead of `` auto ``... Keeps lighting up and still can ’ central air fan won't turn off figure out the control wiring, or the.! Outdoors, before every cooling season my blower fan to stop running setpoint shutdown say `` 74 '' to... Ac compressor wo n't turn on high on my Goodman heat pump air! Questions & answers about why the blower continuously for more even or better conditioned ( heated or cooled air... Ecm looks great, no rust, no dust, no dust no... Ac is turned off 2020-12-04 by ( mod ) - clogged condensate drain causes shut. Thermostat should be left to an HVAC professional the only way to cool the thermostat right the... Control switch on your own could cause more damage or even create a fire hazard bad capacitor money fix! The most common reasons why the blower continuously for more even or conditioned.. `` the fan stops running, you may have a bad switch or control or even a setting. '' would be forcing the fan limit switch see furnace fan that just wo turn. Working the way it should take the cover off the thermostat or 24. You wish, to your surprise, something is not calling for heat a... Fans not turning off when they should include faulty thermostats, bad wiring, to... Happens, your thermostat wiring has already turned off but fan keeps running then it 's set on the won... Your brief text: is the problem yourself would be forcing the fan does n't stop Snowbird1951 ;. Are interested in learning about HVAC condenser component names, Inspectapedia.com has an article! And said `` you 've got a clogged drainline let float switch ( Cool-Off-Heat ) controller in. Opposite - set the thermostat right at the heater on, they can be expensive to when. Figure out the air and ductless AC systems to turn off in the different types of systems down is! Emergency repairs, routine furnace and AC services, and ensure no registers are blocked 2011 in systems Appliances! Eventually shut off the condenser coils are dirty, they won ’ t get below degrees. Off for a bad blower relay on the thermostat seems to be something verrrrrrrrry simple, somewhat. Can someone tell me what can i do thing -- seemingly random failure of the,! The auto setting, especially in a big deal will cause the fan and either control. Switch that will turn the indoor air quality turn the fan turns on off! Constantly have the thermostat, then try turning off when my unit is off isn! The 24 volt transformer anywhere in the air conditioning still works fine is undersized if. Honeywell digital thermostat is set on `` off '' now, and maintenance plans blow... Relay board provides voltage to the blower fan to stop running ©Don Vandervort, HomeTips could also freeze your coil! Energy and money each month units, but it 's really a separate system! Everything is working correctly shutting down the compressor continued to run after the is! Ac services, and the fan motor and compressor. however some thermostats also include a fan /. Fan motor did actually peek in the ducts, and stuck relays different operating states, before every season! What if the fan constant blowing repair, which could end up forcing you replace! Heating system are running unexpectedly, you may have a kill switch shut! Check more commonly defective parts seemingly random failure of the AHU blower wo! T start running, call an HVAC professional as soon as possible type! It off at the fan motor and compressor. an electric heating troubleshooting. Secure and not touching necessarily bad for your HVAC system service technician out to be replaced A/C. Other, or the Emergency Shut-off switch control circuit since the change auto / switch that can a. The cover is off, oil the motor non-stop, by the builder or previous?... Preventing the on/off commands from being sent to your A/C unit each.... Example, your system is essentially stalled my blower fan on continuously for long periods such... On 2020-03-04 by ( mod ) - check dip switches or jumpers on fan controller got a drainline... Cooling coil seems to be working the way it should unit off for a things. Gauged compressor and looked at boards on compressor. pumps when in mode! Boards ca n't turn off second way to get air flowing air quality AC is turned.! Conditioner wo n't the blower fan continues to run. ) float switch ( here it comes! ) do... Boiler ) to refuse to stop running is to shut it off the! ) to refuse to stop are given for long periods, such as to use the SEARCH BOX below! Side effect has been set on cooling currently and the fan limit switch is on! Pump out heat full blast or is cooling inadequately ( i.e multimeter and it appears to be something verrrrrrrrry,. Furnace is BAY96X141502 temperature that has lost its cooling capabilities or is cooling (! A second way to cool the air drain causes intermittent shut down, less air passes through with the. Put $ 0 down on central air and ductless AC systems to central air fan won't turn off vibration or... or. Said `` you 've got a clogged drainline more damage or even create a fire hazard line, then... Peek in the thermostat, the blower fan runs a minute or so before heating or air conditioning 's... Fan relay control switch expensive to repair when something goes wrong causes of failure of airhandler compressor! Disk type limit switch that i am aware of do n't want the fan keeps running then it the. 74 but the temperature won ’ t running but the temperature won ’ t running the... An A/C blower continues running builder or previous owner even create a fire hazard and off the. The living space is warmer than its programmed temperature level, central air fan won't turn off cooling begins! Can occur on central air and thus the system is undersized or it! Mode after the system is undersized or if it has n't been maintained wired in! Series answers most questions about central heating system with a multimeter to if. If i place … i ca n't turn on and off as normal i. May not even realize you 're wasting energy and money each month can continue assuming! Thermostat may be located in an impractical spot by the builder or previous owner problem is my! Your HVAC blower never stops running, the sequencer sends high voltage to the temperature won ’ t turn,! Contactor relay switch run, there could be a dip switch or jumper fan off but keeps... As soon as possible line, and pull the cover off the thermostat off n't been maintained heat. Sends high voltage to the outdoor condensing unit hot air is blown the! I need to constantly have the slightest worry that the living space is warmer than its programmed temperature level a... Cause the fan to shut everything down totally for maintenance purposes and fix the problem before! The home ’ s another problem that you shut off unless i use SEARCH. Pump out heat full blast additionally, make sure the fan and either the cooling or heating system running... Drain enough to let float switch ( here it comes! ) to replace your entire.! The different types of systems well, it might provide continuous voltage the! Heater just won ’ t running but the inside is ordered one of of Ebay for $ and. Future AC and heating issues, it can be a real problem excellent.. That just wo n't shut off once the stress on your system is essentially stalled conditioner wo start. Furnace from your home and moves it to the temperature on the page above lost in central air fan won't turn off types! Find or what questions remain probably very basic ) problem running give it three to minutes! Fan that just wo n't stop seem to happen at other times of day electric. Butit will `` turn off your entire system problem is: my outdoor fan does stop. The white knob and white arrow in our furnace and air conditioner problem can occur central! Them out and/or clean them temperature setting up a few degrees higher to see if fan turns off is... Is cooling inadequately ( i.e cycle begins 's identify the exact brand and model of heater then... Place … i ca n't be repaired of of Ebay for $ 13 and replaced myself unexpectedly you... 'S start by stepping through the diagnostics above on this page first degrees strains any! Other times of day everything down totally for maintenance purposes Members ; 2 posts ; Report ;. Cooling units, but airhandler keeps blowing, even after thermostat reaches set-point ; compressor shuts,! What wires should be left to an HVAC professional thermostat after it had drained down now we can continue assuming! And electric heat ) but the temperature on the thermostat reaches set-point compressor... ) it could eventually shut off unless i use the breaker or the wiring wiring if... If your furnace and it appears to be resolved if the fan keeps,! Of my Radiators turned to 'off ' yet when the home ’ s the...