Merry Christmas! I hope you can easily find and fix the problem. =(, Hi Patrick! We have a good post on troubleshooting pressure switches on the following page: https://arnoldservice.com/how-to-test-and-troubleshoot-gas-furnace-pressure-switches/ I hope this helps you out. I measured the ohms on two new IGN00145 80 volt ignitors that I had and got 14.3 ohms on one and 15.2 ohms on the other. I hope you can easily find and fix the problem If you need a control board or other part please send me your furnaces model number and serial number and I will be glad to look it up. Sorry to hear that you are having furnace problems. If the power going to the ignitor is a constant 120 volts when it is supposed to be glowing and the ignitor is going off and on then this is an ignitor problem. The question would be why is your furnace overheating and causing 4 limits to fail in a short period of time. I’ll also check the light to get the error code. The gas heat should come on by joining the red and white wires together. Steve. Heater guy says its the pressure (propane company), propane guy says its ignition sensor or igniter, but the heater guy tests and says its okay. Then the sequence starts all over again with no ignition of the gas. I hope that you can find and fix the problem soon! I was working on a Trane unit model number TUH2B080A9V3VA, and the hot surface igniter is not glowing. David, Hi David! If one of these safety controls are open then it will not allow the ignitor to glow. Yes, the ignitor should glow and you should be getting power to the ignitor probably 30 seconds to a minute after the draft inducer closes the pressure switch. I would like to suggest that you check to make sure the ignitor is shutting off after the furnace gas ignites. You should hear the gas valve at least trying to open. I just think if it’s rated for low resistance how can it give me that high of a resistance reading. If you would like for me to look up and see what ignitor that your furnace manufacturer recommends then please send me your furnace’s model number and I will try to look it up in one of our parts programs. This … Call Today! This sounds more like a control board problem with the ignitor relay on the control board at fault. If they’re okay, I should have a new board by Thursday morning. Since you are not getting power to the ignitor then this could be an open limit, open rollout, open pressure switch or a bad control board. I copied the following “FYI” off our website: *FYI: A furnace limit is a safety device that is used to cut the gas burners off if the furnace over-heats. Although I think my igniter is bad, the system is never getting to that point. Now my heat wont turn up at all. I do not know what the ohms reading should be on your ignitor but many of the silicon nitride ignitors ohn out with lower than expected ohms. Thanks! If I turn off the power and was a few minutes it usually comes back on. Does this sound like an ignitor going bad? I hope you can easily find and fix the problem. If your furnace lights and the gas stays on for 8 to 10 seconds, then shuts right back off, then you can try to clean your flame sensor with light sand paper (emery cloth) or steel wool. Top Five Reasons Your Furnace May Not Be Igniting 1. Just do not leave the exhaust vent pipe off. Hello – I have an old Janitrol furnace. I hope and pray you can find someone who knows what they are doing with LP furnaces. Everything is just about what to do when it won’t light. This repeats about 5 times and then it stays off (no heat is produced). If you do not hear the gas coming into the burners after the ignitor glows then this is probably a control board or a gas valve problem. I hope you have a nice day and weekend! Furnace not igniting or heating? The computer from what I was told is supposed to recognize a bad HSI or if one is connected. If the furnace continues to overload the circuit, call for HVAC professionals to check it out. The limit should really never be used unless your furnace has a part failure like the blower motor stops, a dirty filter, or if the underside of the AC evaporator coil is stopped up and not allowing air to be expelled through the furnace. As soon as I did the igniter lit up. 3 blinks on a Goodman furnace usually mean a pressure switch problem. A faulty or dirty ignition or sensor is a relatively easy fix, so follow these steps, and you may be able to solve the problem yourself. Pressure switch attached by a small plastic or rubber tube senses the negative pressure produced by the draft inducer and closes. Occasionally, the motor won't come up to speed. Seeing that I power cycled it again to see if it would reset and work on its own. Great video- I diagnosed the problem per your steps and and ever so small hairline crack in the ignitor was the problem. My repair man cannot find the problem – the board is reporting a fault when the furnace is in the failed state but replacing the board did not correct the problem. Make sure that you are getting a constant minimum of 24 volts between W and C when the thermostat is calling for heat. If the burners fail to ignite, the furnace shuts off the gas supply, goes through a purge cycle and attempts to light the burners again. If this does not solve the problem, you may need to hire a professional company to clean your air ducts if airflow is still obstructed. Steve. When the call for heat comes in, the induction fan starts and does successfully close the switch. Whether you need furnace ignitors, AprilAire filters, EZ Flex filters, or another kind of HVAC merchandise, we want to serve you. Have they all just been bad? It will no longer heat up the ignitor. Awesome! You could try tapping on the relay with your fingertip to see if it will release or get a new control board if it will not release. I had the ignition switch replaced and went to bed happy that it was working. Is it possible that the wrong igniter was used in my repair? If any of the safety controls are open then the control board will not allow the ignitor to glow. I took the cover off the new electrical panel and found out that probably half the wires that went into the breakers were loose. This sounds like a control board problem, but you say that you replaced the board and it did not solve the problem. If you are not getting 120 volts then you could have a circuit breaker problem or a loose wire or connection. I turned it off sat breaker and on again and now no glow plug lighting up. You should be able to test these controls with with a volt meter so there will be no guessing as to what the problem is. Sure enough this time the igniter lit up and lit the furnace on its own. This sounds like you have a high voltage issue. PROBLEM: Control has 24 VAC power. Your furnace could also be the cause of the problem. Did I get the wrong ignitor or is there a problem elsewhere? Below we have a picture showing a cracked ignitor. This leads me to believe there is a problem with air flow. I tightened all the breaker screws and we have not had any problems. Great that you saved lots of $$$ doing the repair yourself! No blinking. Steve. Set the multimeter so it can properly measure a resistance of 10 to 200 ohms. I really do not understand why your furnace is going through so many limits. First, you need to turn off the gas to the furnace. Sorry to hear that you have replaced several parts and you are still having trouble with the ignitor not glowing. You would need to test with a voltmeter to see where you stop getting the 24 volts. You might need a new control board. If the new board has a blink code, please try and read the code to see what the board says the problem is. Specifically, if my furnace is supposed to be putting out 120v but is only producing 80v, then that could indicate a problem with the ignitor module, correct?! To make a long story short it turns out that the pressure switch was not making good contact. Then, remove the front panel to find the ignitor or ignition sensor. The unit, Trane Xr90, goes through the cycle, does not ignite, and then eventually locks out. You can use an ohm meter to check the ignitor to make sure it is good. If the sensor or ignitor is dirty, it will need to be cleaned. That fixed blower issue, but obviously something else is going on. Most of the time with an ignitor problem the breaker will stay on. At Assured Comfort, we just want to wish all our clients, staff, friends and family a safe and healthy holiday season. Sounds like you are not getting voltage to the ignitor which could be caused by an open safety control like a rollout switch, limit switch or pressure switch. If your thermostat has batteries make sure they are good. Inside the unit is extra clean, as was filter. The furnace had been working fine up until today. On the top we have pictures of three different types of flame sensors. Hi Tracy! Steve. PayPal, Secure Credit Card, Amazon Payments, and Mail in Check or Money Order. If all of those check out good then it almost has to be a control board. Ignitor will not glow. Hi Ron! The trouble guide says this could be due to a broken ignitor or an open ignitor circuit. Any kind of air restriction in your supply or return can cause a problem too. God bless you all! Hi Tracy! Thanks! And why, will this unit not heat, when this same switch, when jumped, will not work at all. Thermostat calls for heat. Read More. It doesn’t go on because it’s not getting a signal that the igniter is on, so I can’t tell if the solenoid is working properly, but I have a hunch that it is. Place your order today! The unit is 14 years old and hasn’t had service or maintenance done in 5 years. Your furnace wiring schematic should show any fuses. The furnace hot surface ignitor does not glow. We have UPS Ground, Next Day Air Saver, 2nd Day Air, 3 Day Select and UPS Sure Post shipping options in our shopping cart. If all the safety controls check out OK (closed) then you probably have a bad ignitor relay on the control board and you will need a new control board. If you are getting 24 volts to the gas valve and it is not opening up to allow gas to flow then you probably have a bad gas valve. Hi Jake! I have cycled the unit several times, heard the click as if the gas valve opened and still no ignition. Thanks! We have processed over 25,000 Successful PayPal Orders! Steve, I ran out of propane, got it filled up and went to start the furnace it ignited, and wouldnt ignite back. When I put a meter to the igniter socket I am measuring 40v. However, not all furnace problems are easy DIY repairs, but it is worth a shot before you pick up the phone to call a certified HVAC technician. Ignitor is new, BTW. 919-480-2727 Service Since 1986. I tried to perform reset sequence from the Lennox manual but still got no power. Steve. Above 90 ohms the ignitor is considered bad. * Schedule Service Online & Save 10% offer is only applied to the service call fee and does not apply to any additional service work. You should have 24 to 28 volts AC between R and C. If you do not then you have a low voltage problem which could very well be a low voltage transformer that is burnt out. Then, remove the front panel to find the ignitor or ignition sensor. Hey, I have a Goodman Furnace Model GMP100-4. The furnace gas valve for this type of furnace is identifiable with its solenoid designations: MV (main valve), PV (pilot valve), and PV/MV (common). Seems to be popular. On Bryant Carrier furnaces we will need the product number. The furnace will come on (humming noise) but the pilot light won't ignite (no heat). I have a janitrol heating unit model GMP075-3 REV A and i bought a new hot surface ignitor. Steve. Please help, I would recommend checking to see if you are getting 24 volts to the gas valve when the gas valve is supposed to be opening. Still have no real idea what it could be . As soon as I turn it on, and raise the temperature on the thermostat, the unit goes into normal operation, instead of performing the igniting sequence. Is this likely to mean I need a new control board? Steve. The control board’s LED is steady on. You help would be greatly appreciated. Normal ignitors ohm out between 40 to 90 ohms. This is probably the most helpful site I have found for diagnosing furnace problems. When a furnace is set up properly with the right temperature rise in the heat exchanger then the furnace should never go off on limit. Thanks – how can I verify that the rollouts and limit is closed? Draft inducer motor starts. Hi Victor! the kind of furnace that is in your home. If the ignitor is getting 116 volts while attached it should start glowing. Steve. I would suggest checking the limit and pressure switch to make sure they are closed when the furnace calls for heat. I do not think that I would be stumped if I was able to trace down with a voltmeter why your furnace will not run. The furnace controller monitors these sensors constantly. Often, newer electronic thermostats will display an error code if something is wrong. But from what I understand it is supposed to send between 70-80 volts but I got a reading below 70 around 65Volts, and another reading of 86 volts. I would make sure that all your safety controls like the limit, rollouts and pressure switch are all closed. Your email address will not be published. Maybe some ice got into the vent pipe or the combustion air vent pipe. Thank You Cosimo Roarco Have a nice day, Sorry to hear that your ignitor is going out often. Thanks so much for sharing that sometimes it is hard to see that an ignitor is bad if it has a hair-line crack. The Thermostat If you want me to look up parts please send me the model number of your furnace to our email address: email@example.com. There is no blinking diagnostics light on the circuit board. We have a couple of posts with Youtube videos that I hope will help you out on the following pages: https://arnoldservice.com/problem-my-furnaces-ignitor-does-not-glow-this-could-be-a-pressure-switch-limit-roll-out-switch-or-furnace-control-board-problem/ and also on the following page: https://arnoldservice.com/problem-i-purchased-a-flame-sensor-from-you-for-my-goodman-furnace-the-new-flame-sensor-did-not-fix-the-problem-my-furnace-still-lights-for-7-to-10-seconds-and-then-the-gas-goes-out-what-could-be/ In the YouTube video it shows how to test a flame sensor. Problem: Furnace will not ignite the gas to produce heat for your home. The next step would be to measure the voltage as you suggested above. Hi Mark! If it is neither of these reasons causing the issue, try turning the fan switch to "on" to force the furnace to start blowing air. We hope this will help you troubleshoot and repair your furnace. I am now getting the 4 flashing light code which I understand is a limit switch. I assume that your draft inducer is running but the ignitor will not glow. There is not really a way that I know to determine how long an ignitor will last. Steve. If any of the safety controls open up because they have over-heated or not getting the right pressure then the control board will not allow the ignitor to glow. This is probably the most common malfunction in gas furnaces. Steve. We have lots of furnace troubleshooting advice on the following page: https://arnoldservice.com/gas-electric-furnace-troubleshooting-simplified-2/ I would suggest going through the troubleshooting flow chart to see what is wrong: https://arnoldservice.com/wp-content/uploads/2014/12/furnace-troubleshooting-flow-chart.pdf We also have lots of troubleshooting questions and answers on the following page: https://arnoldservice.com/furnace-troubleshooting-questions-answers-index/ If you have any specific questions please let me know. Modern gas- or oil-fired furnaces have several safety sensors that check on furnace operation. But I’ve just never seen anything like that before, nor can I find any guides about what to do when it won’t go out. I hope you can easily find and fix the problem. Schedule Service Today. The main blower coming on before heat concerns me also. Inducer come on and glow plug worked but no gas to light. If any of these are open the the ignitor will not glow. If your ignitor will not light up then this could be caused by many different problems. Here are other reasons your furnace may be short-cycling. Your furnace man might need to adjust the pressure on the furnace’s gas valve. I have taken the circuit board out to view, and it has no apparent flash marks. Sorry, you are having this problem in this cold, cold weather! If the ignitor is staying on then you probably have a stuck relay on the control board. I hope you find and fix the problem soon! When it has cooled down to a safe temperature, check the motor. I also get no sound from the gas valve after what I think should be sufficient time for the ignitor to heat up. Can I put a clamp-on meter to wires from valve to ignitor? I don’t smell any natural gas in the basement or around the burners. It would be best to send this information to our firstname.lastname@example.org email address. I would make sure the gas valve pressure is right first. I power off the unit and then cracked the housing with the igniter (as I’m typing this I realize this probably wasn’t wise…but it was freezing) and then flipped the power on. One of the most common problems is that the blower motor makes a humming sound. I hope you can easily find and fix the problem. The rollout switches could be wired in series with the limit and if one of the rollouts are open then it might not supply power to the limit. I’ve replaced the ignitor and the flame sensor. I would suggest that you test the ignitor with an ohm meter to make sure it is good. Make sure that your furnace door is good and secure. The only things I have not changed out is the small transformer and the circuit board. I would strongly suggest that you make sure that the fuse is good on your control board and make sure you are getting 24 to 28 volts AC between the R and C (com) terminals of your control board. In the process of removing the burner tubes, I also had to remove the flame sensors and put them down onto the metal housing while the power was still on. A gas valve that is adjusted to supply too much gas heat input can cause the limit to go off too many times too. If you have determined it is not one of these problems, or you know that it is the motor or wiring causing the issue, you should call a. click on the button below to schedule a service today. Hi Mr. DeGuilio! Managed by Wooassist - Woocommerce Support www.wooassist.com. Most ignitors read between 40 to 90 ohms if they are good. One of the easiest solutions to fix a broken furnace is changing the air filter. Thanks! Sorry to hear your heat is out. If you do have blink lights on your control board the board should tell you what the problem might be by reading the blink code. Regardless, it does have an HSI and the ignitor model you mentioned in your email appears to be the correct one. One of the most common reports homeowners have when their furnace will not ignite is the clicking sound of the furnace about to come on, but then silence and no heat. There is a power disconnect switch by the furnace. Not sure if I have a problem or not, have you ever seen a hot surface igniter not turn off after the furnace is lit? Most of the time the blink code key is located on the furnace’s blower door or cabinet door. Thank you, Hi Mauro! It stopped working all together the other day, went to check it out and noticed that it was in Ignition lock out mode. You could also have a control board problem that is not allowing current to the limit. CODE: Ten LED flashes PROBLEM: Polarity is reversed Installed a new igniter and have the same problem, the igniter will not glow all the times, it works on an intermittent basis. If you are not then I would suggest looking to make sure that all the rollouts are closed. The electronic ignition system has broken. I also checked for power to the gas solenoid, and I”m getting the 24V signal. The part number for the DSI is 43K3101. $22 vs a $150 quote. New ignitor solved the problem. Thanks! I hope you can easily find and fix the problem. On the bottom is a picture of a hot surface ignitor. Hi Jeff! In all cases, it is important that you don’t have anyone work on your furnace that is not trained as an HVAC specialist. It sounds like your gas air mixture is not right since it is burning yellow. This could be a low voltage transformer that is out, a fuse that is out or it could have shorted out your thermostat or another control. If the furnace is experiencing problems that could result in a fire, it may fail to ignite properly. Sorry that I can not be of more help or give you any other advice. My question is why is my York 80 eating these limit switches. I am sorry that I can not make a recommendation because it takes special tools to get the gas/air mixture right on an LP furnace. Several breakers started tripping for no reason. The igniter is brand new and reads about 17 ohms when checked across its terminals (ohm reading is correct for this igniter unit). I checked the voltage to the plug connection and it reads 116 volts once the inducer fan and pressure switches are activated. It performs the startup cycle, the fan blows but I do not hear the gas coming on nor does my ignitor light up. If all these check out OK then I would think that your control board could be at fault. Heating Problem: My Electronic Ignition Furnace Won’t Ignite The standing pilot light was the regular way to ignite gas-powered furnaces for almost as long as these heating systems have existed. So sorry to hear you are having this trouble and a run around between the propane company and furnace man. Hi Scott! The problem could be coming from the control board or any of the safety controls (pressure switch, limit or rollout switch). So here’s my question- Is there a specific sequence that is supposed to occur before the IFC sends power to the igniter, like a time delay, (other than the normal 30 seconds for venting), or another switch closing? Also the blower was still running which I thought without a flame the flame sensor would turn the furnace off. We sell furnace limits on the following page: The furnace’s control board might not be supplying the voltage to the ignitor.