Newer gas furnaces are far more complex than earlier models so you need expert advice. If you are having furnace problems, plenty of furnace troubleshooting tips exist. A gas furnace, regardless of its age, is still susceptible to problems, such as electronic ignition failure.Should this happen, the gas furnace ignitor will stop working, and the furnace will be useless. Step 1 Start with the basics. Not only is your home uncomfortable, but depending on the weather, it can also put your home at risk for bursting water pipes, mold and a host of other problems. If you only see the leak when running your air conditioner, chances are that the water condensate line has a clog or a leak. Furnace Not Working? You can try replacing the filter and checking the power and gas line to your furnace. High-efficiency furnaces are often known as condensing furnaces because they have a second heat exchanger that extracts additional heat from the air that passes through the first heat exchanger. So whether your limit control switch is shutting down your furnace because it thinks your furnace is overheating, or because the limit control switch itself is damaged and needs to be replaced, I’d say that replacing this switch is your next best step in troubleshooting a furnace that is not blowing air. If either the return or the vents are blocked, the furnace cannot do its job. Reasons for your gas furnace not working can be complicated or very simple. I’ll describe what the gas valve does and why it’s important. The Spruce uses cookies to provide you with a great user experience. Do you hear the furnace trying to light? If it seems like the gas line is not the issue and the gas is flowing to other appliances, check to make sure the gas supply to the furnace itself is open and clear. In very cold weather, this activity might be normal and necessary to keep your home at a comfortable temperature. Instead, they make use of electronic components. If it's still not working, consult with a professional. Thermostats can be sensitive and when malfunctioning, can prevent your furnace from doing its job. A gas furnace that is frequently cycling from “On” and “Off” modes is indicative that the furnace has a problem with its thermostat or the air filters may be clogged. The other reason the blower does not turn off could be because of the control switch on the fan. A hot-surface ignition system uses an electronically controlled resistance heating element, not unlike a light bulb filament, to ignite the gas burner. It will likely lead to you needing to make a replacement. Furnace not igniting. The furnace doesn’t heat enough : In addition to a clogged filter, a furnace may not produce enough heat if it’s the wrong size for the space. And it's also easy to replace the thermocouple if it is faulty. Is your furnace ignitor not working or not glowing and the furnace is not igniting the gas? Cut down on energy costs and prevent damage to your furnace by addressing a gas furnace that's overactive or short cycling. Sometimes the furnace motor can overheat and trip the reset button. Often a service technician can tell you about factors that are common to your furnace make and model that you can solve yourself in the future. Simply look for a standard wall switch on or near the furnace and check if it’s in the on or off position. We have grown accustomed to warmth on demand. Return the breaker to the on position to restore power to the furnace. When cold weather hits, it is imperative that your furnace is working properly and producing enough heat to warm your home. Once you do, you will be able to take stock of your options and pursue the strategy most likely to fix the issue cost-effectively. Both gas and electric furnaces require electricity in order to work. On old furnaces, the standing pilot light can go out due to a strong draft, a dirty orifice in the pilot burner, or dirt in the gas tube. Hey guys, today we’re going to talk about troubleshooting a furnace gas valve. Introducing "One Thing": A New Video Series, Heats it up with a gas burner using a steel heat exchanger, Distributes the warm air with a blower motor through your home's ductwork. Sorry about the poor camera work! Sounds like a no-brainer, but if repairs or maintenance work were recently performed on your furnace, and it’s not working for some reason, you may want to check to ensure that it was turned back on. Fortunately, problems with electronic ignitions sometimes can be fixed yourself. 9. If not, the gas valve and spark ignitor will not work but the blower will. Get daily tips and tricks for making your best home. By using The Spruce, you accept our, Review of Gas Furnace Types and Efficiencies, 3 Things to Check When Your Furnace Stops Working, How to Troubleshoot Electric Ignition Furnace Problems, How to Light the Standing Pilot Light on a Gas Furnace, Troubleshooting an Electronic Ignition Furnace That Won't Light, How to Replace a Furnace Thermocouple or Electronic Flame Sensor, How to Troubleshoot a Gas Furnace That Produces No Heat, Troubleshooting an Intermittent Pilot Ignition System, How to Check a Pilot Light on a Gas Furnace, Troubleshooting Common Problems With a Gas-Fired Hot Water Boiler. Finding out that your gas furnace is not working can be a major inconvenience, so it’s vital that you understand why. If your Lennox gas furnace won't start, doesn't provide enough heat or continuously cycles on and off, a bit of troubleshooting might just solve the problem without ever having to get a repairman involved. There are three types of thermostat systems used today: millivolt, low voltage, and line voltage.​ Make sure you have installed the correct type for your furnace. Step 8: Furnace Won’t Turn On – Check Your Ignition Sensor Now you are starting to get into the weeds a bit. Remove any obstructions from vents inside the home so static pressure in the system will distribute evenly. Frequent cycling. If the switch is not allowing the blower to turn off, this part will need to be replaced. The cold returning air enters back through the air filter into the furnace to complete another heating loop. Check the furnace’s ignition. Make sure the thermostat is switched to heat, the fan is on, and the temperature is adjusted to your target warmth. For gas furnaces: Check the pilot ignitor, flame sensor and/or pilot light. Without it, we would still be huddling around wood fires to stay warm. The furnace or heat pump was working fine before the storm, but when power is restored the heat still isn’t coming on. Potential simple solutions include replacing the filter, as a clog could be making the noise, and oiling the blower motor. If there is a reset button on your furnace, turn the valve to the pilot position and hold a flame to the dedicated pilot gas tube while pushing the button for about 30 seconds. Modern furnaces come with safety switches on their front panels that don’t allow the furnace to engage if it’s not properly closed. Or the thermocouple might be faulty, causing the gas supply to shut off. Depending on your unit, you may have a pilot light or an electronic ignition. Some problems you can fix yourself, but it might save you money in the long run if you get a professional in right away. Troubleshooting Furnace Problems. If the breaker continues to trip, there may be an electrical problem with your furnace or your home’s wiring, which will require a professional to diagnose and repair. Here are a couple things to check before giving your local heating and air conditioning contractor a call. For a furnace to work it needs to draw in air and push it back out again. Make sure there is power to your thermostat and that there is no dust or debris in its components. Do not flip switches on the way out and do not stop to gather anything you find invaluable in the moment. Sometimes, it is more stubborn. That said, if they do not work for you or if you feel uncomfortable completing any of them, give your local HVAC professionals a call. Cold? If the electronic ignition has a problem, your furnace might produce little or no heat, it might cycle frequently, or you might have an overactive blower. But otherwise, it could signal a problem with your furnace. This switch usually powers the low-voltage thermostat as well as the furnace itself. Problems with your pilot light can cause your gas furnace to blow cold air. While you are probably better off leaving the difficult problems of thermocouples, wiring, heat exchanger, and blower motors to a qualified professional, there are a good number of things you can check before you phone a qualified HVAC contractor for furnace repair service. Filters should be checked at least every three months and most manufacturer’s recommend monthly replacement. Fixing a gas furnace: this is a real-time look at how I'm keeping warm until the new gas valve comes. Throughout the process, if you suspect a gas leak you must deal with it immediately. A forced-air gas furnace, whether conventional or high-efficiency, is an appliance that does the following: The heated air then cools down throughout your home and returns to the furnace through return air grills and ductwork. Then, turn the gas valve to the off position and wait five minutes. Problem 13 Noisy Furnace or Duct Work. If your furnace stops producing heat or is blowing cool air only, there are several possible culprits. If your furnace is not working, you could end up facing a variety of problems. Rumbling, squeaking and rattles aren’t normal. If you don’t immediately discover the source of the odor and the smell is strong, exit your home while also leaving the door open. If issues continue to persist, you may also need to replace your thermocouple. Perhaps your blower motor has burnt out and you need a new one. Locate the correct fuse in your service box and check to see if the breaker is tripped (flipped up halfway or in the off position). Newer conventional furnaces don't rely on a standing pilot to ignite the gas burners. Electronic ignition occurs typically in one of two ways: intermittent pilot or hot-surface ignition. Luckily, relighting your pilot light is fairly simple. Depending on your unit, you may have a pilot light or an electronic ignition. Gas leaks are dangerous. If you smell gas, you must respond immediately. 10 Easy Things to Check When Troubleshooting a Furnace Gas Valve. Larry Campbell is an electrical contractor with 36 years of experience in residential and light commercial electrical wiring. Since 2012, high-efficiency condensing furnaces with AFUE ratings of at least 90% have been increasingly popular, and they require different troubleshooting techniques. Your thermostat may have been accidentally turned off, … These are often old furnaces that have standing pilot lights, and they are usually noncondensing furnaces that vent exhaust gases through chimney flues rather than through PVC piping. If it is not working either, then you’ve found your problem and it’s time to call the gas company or get the propane tank filled. Check to see if your panel door is secure. The furnace switch is usually mounted on a wall near the furnace, or sometimes even on the furnace itself. Residential If you have a gas furnace, the pilot light must be on for it to work. Contact a professional to assess your situation and provide service. Browse Helpful Items on Amazon • Furnace Thermocouples • Thermostats • Furnace Filters • Furnace Motors (which may need resetting or replacing). The valve is closed when it is perpendicular to (or across) the gas line. Furnaces and thermostats must be correctly matched to one another in order to function correctly. 4. This can be very dangerous and should be addressed as soon as possible. Ductless Split Systems Here are eight common problems you may encounter with a conventional gas furnace. Even with proper maintenance, however, furnaces can break down and develop problems that impede regular functioning. If the furnace still doesn’t work, be sure the thermostat isn’t faulty. Before calling in a heating repair professional, spend some time diagnosing the problem and seeing if you can fix the problem yourself. Try replacing its batteries if the display on a traditional low-voltage thermostat or wifi thermostat is not indicating power. Either system can go bad over time and need repair or replacement, but sometimes the solution for a furnace not working is as easy as relighting the pilot light or replacing a thermocouple. Problems with a thermostat can manifest as a furnace that produces no heat, wild temperature swings, or a furnace cycling on and off too frequently. Flip a switch or adjust a knob and within minutes, hot air bathes us in comfort; unless your gas furnace is not working. See How to Test a Thermostat. Unfortunately, furnaces need regular professional tune-ups and homeowner upkeep to run strongly and efficiently.. Instead, these gas furnaces use an electric ignition system that lights only as needed. Most of the time it ends its hiatus without protest. Pairing the wrong type of thermostat with a furnace will cause operating problems. Read your owner’s manual if you’re unsure. Is your pilot light on? The sounds may indicate a mechanical problem, airflow reductions or a clogged burner. Besides the need for consistently comfortable temperatures, this issue could cause long-term safety issues to your home, making it very important to address. Another easy way to tell if the gas is on and working properly is by starting another gas burning appliance, like the stove. Furnaces usually take long vacations during the summer months. Once you've ruled out the common culprits with the furnace itself, such as a dirty filter, check the thermostat. Gas furnaces cannot operate without electricity. Serving Homes and Businesses Throughout San Diego, CA, Global Heating and Air Conditioning 473 Vernon Way El Cajon, CA 92020, Heating ​​The intermittent pilot system uses an electronically controlled high-voltage electrical spark to ignite the gas pilot, which subsequently lights the main burners when the thermostat calls for heat. Global Heating and Air Conditioning The most common reason for your furnace not igniting your burners is the failure of your pilot light. It’s a good idea to test your furnace with a trial run before you will absolutely need the warmth it provides. Is your furnace blower motor not working and there is no air coming out of your vents? Ignition Problems. Most modern gas furnaces have an electronic pilot igniter coupled with a flame sensor rather than a physical pilot light. You might be able to address some repairs on your own while others will require a professional. Bob Formisano is a licensed architect and builder with 30 years of experience in the industry. If it does not operate correctly, and you cannot troubleshoot the cause on your own, call a professional for home heating repair service. 5 Common Problems With High-Efficiency Furnaces. ← Commercial Heater Installation: What to Expect, Pros and Cons of a Programmable Thermostat →. Either system can go bad over time and need repair or replacement, but sometimes the solution for a furnace not working is as easy as relighting the pilot light or replacing a thermocouple. Conventional furnaces are generally simple in design, but occasionally things don't work quite right. There are several possible causes to investigate, including a dirty filter, a blocked exhaust vent, or a faulty thermostat. Like most home systems, furnaces that sit for long periods of time may have developed an issue when idle. The furnace doesn’t heat at all: A furnace that doesn’t perform its main task may have problems with the thermostat setting, power, gas or the pilot light. A newer gas furnace – typically manufactured from about 2010 and later – does not have a pilot light that stays lit all the time. Try These Troubleshooting Tips. Remove the outer cover and clean the unit if it appears dirty. Easy potential fixes include: Cut down on energy costs and prevent damage to your furnace by addressing a gas furnace that's frequently cycling on and off, or "short cycling." I wanted to expand on our recent gas furnace troubleshooting series by going into each part of a furnace sequence of operation. Sometimes there is a humidifier mounted on the furnace or the return air ductwork. Air Conditioning Once outside, turn off your gas supply at the valve near your meter. Commercial For gas furnaces, even though gas is the fuel that provides the heat, electricity is needed to operate the blower motor, relays, circuit boards, and more. What Is a High-Temperature Limit Switch on a Furnace? From a faulty thermostat to a dirty filter, there are several possible causes to investigate. The main gas line coming into your home may be off for some reason; a call to your gas company should alleviate this. After the motor has cooled locate the reset button and press it. Older devices need to be perfectly level, so if the thermostat has been moved, make sure it is put back in its original place on the wall. Contact, © 2021 Global Heating & Air Conditioning | LIC #988444 | Powered by CNG Digital Marketing | Privacy Policy. Here are the top seven parts that, if defective, will likely prevent the furnace from heating, and all of them can be replaced by the average homeowner: Faulty Igniter – If the igniter is faulty, it will be unable to ignite the gas into a flame to create heat. For instance, your furnace might overheat or underheat your home in spite of how you've set your thermostat. If you smell gas do not light any matches or turn electrical switches on or off. When you discover that the blower is not working on the gas furnace, you need to contact a professional to replace it for you. We all take heat for granted. Yearly Maintenance A gas furnace should turn on and off throughout the day. When you finally decide the heavier blanket is not cutting the mustard in the early morning hours, you want your unit to get back to work. All furnaces have a basic power switch. The pilot light going out is one of the most common reasons that a gas furnace fails to produce heat. When you know how to identify when your gas furnace ignitor is not working, you can have it taken care of by professionals rather than suffering in the cold.This way, you will be able to determine if the problem is something that is a simple fix or one that requires the help of a professional HVAC contractor. With a gas furnace, the pilot light may have gone out or the gas valve may be shut off. If your furnace blower runs constantly, two likely reasons should be considered: Excessive noise in your furnace almost always indicates a budding problem that can turn into an expensive repair if you ignore it. If simple fixes don't do it, it's probably time to call in a pro. Furnace Turns On and Off Too Often. Your first step should be to determine where the water is coming from. Gas leak. A typical issue that comes up with gas furnaces is the electronic ignition. If your furnace is still not working, check these items: House batteries must be at 10.5 volts or higher. Here are some common reasons why your gas furnace might stop working or performing at optimal efficiency. Some common symptoms exhibited by your furnace might actually be due to a faulty thermostat. But what many homeowners don’t understand is that water is a natural byproduct of a gas furnace or air conditioner at work. Then our idyllic reality is shattered and we want answers in a hurry. You might hear loud banging, high-pitched squealing, or just a low-pitched humming. My Gas Furnace Is Not Working – Now What? A furnace is crucial for comfort and survival in cold winter weather. If you can spot problems with your gas furnace when they happen, you will be able to get the help you need to have your furnace fixed right away. A gas furnace blower that does not turn off could also indicate a problem with a faulty limit control switch. If your gas furnace is not working, there are a few things you can do to troubleshoot the problem. 6. First, confirm that the light is out. 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