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. 1. While the cover is off, oil the motor on older air conditioners. 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) How your fan normally works. Location of Your Thermostat . 1-800-269-2609 24/7. Examine the external wiring and make sure it’s all intact — sometimes, animals can chew on wires and cause damage to your unit. A compressor that shakes or stutters when it’s turned on, otherwise known as hard starting. Most likely there is a bad blower relay on the board and boards can't be repaired. I've got the same problem, as posted On 2020-03-04 by Forrest. Have you checked for shorted wires anywhere in the control circuit? If the fan blades are bent or dirty, straighten them out and/or clean them. Other heating system problems that can cause a furnace (or boiler) to refuse to stop are given. Fan and compressor at the same time. InspectAPedia tolerates no conflicts of interest. The thermostat seems to be working the way it should. - my furnace will not shut off i have to use the breaker to shut it off. But I have checked it with a multimeter and it appears to be working correctly. - 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. 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. He saw some water in the switch cup, and said "you've got a clogged drainline. So when something goes wrong with the fans, it can be a real problem. Verify the switch on the thermostat is set to “Fan” or “Cool” and make sure the air conditioner is turned on. When the fan goes down there is no way to cycle the air and thus the system is essentially stalled. You mean you think it's the ECM problem (bad or set that way) as well? 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. 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. Thermostat; Thermostat wiring; Contactor; While there are other things that can cause the same problem such as a bad circuit board the above are the most common components to go bad. or the refrigerant line could be damaged. This problem began with turning the furnace on for the first time this season. First, confirm that the room thermostat is not calling for heating or cooling. Although your fan never shuts off, your heating and air conditioning still works fine. My Amana/Goodman ARUF3714C airhandler keeps blowing, even after thermostat reaches set-point; compressor shuts down, but airhandler keeps blowing. Contractor came out, gauged compressor and looked at boards on compressor. - ADP Air Handler with heating/cooling coils: fan control, Ovsa This isn't necessarily bad for your fan, but it is usually a sign of a bigger problem. If the fan keeps running then it's not a thermostat setting. Listed below are the 3 most common reasons why the blower fan continues to run after the system has already turned off. If the fan continues to run, there could be a problem in the thermostat or the wiring. Apologies for the delay. 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". This controls the low voltage supply. It probably won’t surprise you to hear that fans are a huge part of your HVAC system. my question is what controls the fan on/off? The most common reason that your Air Conditioner fan won’t turn off is because a stuck relay keeping the circuit closed. These problems are not easy DIY repairs and should be left to an HVAC professional. Please look through those steps and let me know what you find. BUTIt will "TURN OFF" the outside fan IF it is switched to "OFF position MANUALLY. BillYour service tech might check for a bad control board or ice blocking on the cooling coil. Clean it up. Customer reply replied 7 years ago. When the thermostat calls for heat, the low voltage activates the sequencer, which in turn sends high voltage to the electric heat elements. Additionally, make sure the thermostat is on the auto setting. Air conditioner won't turn off? at THERMOSTAT WON'T TURN OFF. out FAN LIMIT SWITCH INSTALLATION & WIRING. Well, it turned out to be something verrrrrrrrry simple, but somewhat elusive! Now we can continue by assuming you're convinced the trouble is right in the air handler. Go to the thermostat and turn the indoor temperature setting up a few degrees higher to see if the fan turns off. An air conditioner that has lost its cooling capabilities or is cooling inadequately (i.e. salsabil. 4. one of the situations described at FAN WONT STOP - THERMOSTAT SWITCH. 2. 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. Or this may be the IO Manual for your unit: 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 What do I need to do, if I don't want the fan constant blowing? Blower Won't Work on Central Air. The board on the air handler controls the blower. Most likely a capacitor. 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. There’s a problem in your thermostat wiring. ("Man" or "Manual" would be forcing the fan to run.). warm or hot air is blown into the house). When fan stops spinning…Turn a/c unit off for a few minutes, then back on and fan spins for awhile. It worked. Some condensers have an on/off switch and some just have a kill switch to shut everything down totally for maintenance purposes. The side effect has been that the furnace blower will not shut off. It's a hot day and your air conditioner won't turn on! I called 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. like a top since then. 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. continuous, with no shorts to any other lines. 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. Turn the air conditioning unit's breaker off at the main electrical panel. 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. On 2020-12-04 by (mod) ... One problem that you may experience with your outside air conditioner is when the fan does not come on. what's shutting down the compressor." Remove the access panel with a screwdriver. A dirty air filter could also freeze your evaporator coil. 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, Details about the manual FAN ON or FAN AUTO ON switch right at the furnace or air handler at the manual. You have told the thermostat to turn off the HVAC equipment. If there is a problem with the relay board, it might provide continuous voltage to the compressor. The problem is *intermittent*--sometimes airhandler shuts off, sometimes it just runs and runs (not the Nathan On 2020-07-15 by Steve (in GA) The thermostat reaches the desired temperature, the indoor unit shuts off, the air stops blowing, but the outdoor unit keeps on running. He conjectured about putting a pull-down resistor across G and C, to bleed any stray/leftover voltage at setpoint shutdown. Ac starts out cold for a few minutes then the hole system out side shuts off. All lines were by (mod) 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). Broken Relay Switch or Short Circuit: If only the fan is running, there may be a broken relay switch preventing the settings you enter on the thermostat from being sent to the fan. I can't turn off the honeywell thermostat fan. intermittent results, I figured the compressor was shutting down for some type of overheat situation. Check whether your fan is set to On or Auto. A. Ant5. This air conditioner problem can occur on central air conditioning systems or on heat pumps when in cooling mode. 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. Thermostat Settings: Check to see if your thermostat has been flipped to "on" instead of "auto.". In that case, it will keep running until the outside weather improves. Having a central air problem. Nathan First let's identify the exact brand and model of heater and then look at the manual to see what settings are available. For a safe and fast repair, contact Petro Home Services. my furnace will not shut off i have to use the breaker to shut it off, i have a colman electric furnace that wont shut off, On 2020-11-13 by (mod) If your air conditioner won't turn on, it's important to troubleshoot a few key things before you call in an HVAC technician, as this can save you time and - more importantly - money. This problem began with turning the furnace on for the first time this season. An AC compressor that won’t turn on. 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. compressor. Blower motor won't turn off [ 3 Answers ] I have a Carrier central air and furnace model 28GS 036 000. Fingers crossed that this solved it! 3. 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? It's running now, blowing cold air. At the room thermostat: the FAN-AUTO-OFF or FAN ON/OFF switch on the room thermostat should be checked. 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. Usually: "Push-in" position on this (Honeywell) fan limit switch is for continuous fan operation and "Pull out" position is for automatic fan operation. 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. ... Lennox Air conditioner won't turn off. What wires should be 'shorted' to each other, or to ground, during different operating states? Let me know what you find. The refrigerant in the A-coil picks up the heat from your home and moves it to the outdoor condensing unit. The compressor would run, cool the coils, and condensate would begin accumulating-- If the equipment was running give it three to four minutes to shut down. Hi looking for some technical help with our HVAC system. I would replace the sequencer, fan switch and limit switch (high heat), at the same time, they should all cost around a $100 more or less. I'm wondering about either the control wiring, or the 24 volt transformer. Then it stays running until the next morning again. thank you, I shall ohm out the control wires from thermostate mount plate, and check for shorts. These diagnostic steps are for an air handler, blower, or furnace fan that just won't quit running. But on some it might be a dip switch or jumper. On most equipment there's actually a user operable switch that will turn the fan to run continuously. Small problems often build up overtime, so you may not even realize you're wasting energy and money each month. I am a new homeowner and I found the blower fan (Genteq Endura ECM FM19, 1/2 hp, 230VAC) installed has been running constantly. Good going on those diagnostic steps. Though I very well could have missed things as I get lost in the different types of systems. 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. 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. 1. The other possibility is wiring--if there's some random short or open, responding to equipment vibration or...? 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. With the thermostat off and the fan set to auto. enough to let float switch drop, and enable the compressor to run. I suspect it could be a bad relay. Fan won't turn off on Lennox central air and heat The system continues to run even when in the "off" position, no matter if it's set on heat or cool, and no matter how or low I turn the thermostat. Blower motor won't turn off [ 3 Answers ] I have a Carrier central air and furnace model 28GS 036 000. 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. The fan will not shut off even when the thermostat 3-way switch (Cool-Off-Heat) controller is in the "OFF" position. Your Account. posted 2010-Mar-27, 5:48 pm AEST ref: whrl.pl/Rcdy3Q. … The fan control should be set to AUTO. When your HVAC blower never stops running, your first stop is the thermostat. We explain what switches or controls may be set improperly or what else, such as a shorted wire, can cause continuous HVAC fan operation. 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