When the filter is clogged, ignition can be affected and the result is your heating not blowing hot air. If you're lucky, the problem may be as simple as changing a fuse on the circuit board. If your thermostat is set to "on" instead of "auto," it could be causing your furnace to blow cold air. Start by turning your heater off and inspecting the filters. Unfortunately, more complex issues in this department typically require an expensive replacement. If you have an oil-fired furnace, its filter can become clogged with dirt and debris, just like an air filter on a gas-fired system. Replace or clean dirty or clogged filters. A friend of ours bought a new house recently. Try changing the air filter and restarting the furnace. Try turning the furnace off via the power switch. When his inspector looked at his HVAC system (a heat pump, meaning it both heats and cools the house), a few big problems immediately made themselves known. Winnebago View Change the setting back to AUTO, and you’ll have heat again. With that said, even if you recently changed your filter you should check it again. When overheating, your furnace can trip a high limit switch, causing the furnace burners to shut off so that the heat exchanger does not crack. If your furnace starts blowing warm but then quickly turns cold, the flame sensor may need attention. As a pilotless burner owner, you'll want to keep your fingers crossed that your issue isn't related to your burner's circuitry. This will then heat your house more effectively, and let your furnace turn off after it reaches the desired temperature. If your furnace has a fan control, it may be adjustable. It is usual for cold air to enter the heating system until it is warm, and then for warm air … 10 Common Reasons Why Your Furnace is Blowing a Cold Air Read More » The thermostat of your furnace has a fan with two different settings: “on” and “auto.”. When the air temperature reaches the setting you’ve chosen — let’s say 70 degrees — the furnace can take a break until the air drops below 70 again. Do this: Ensure your thermostat’s fan setting is set to AUTO, not ON. If you find that you go to bed comfortable and wake up freezing because instead of your heater delivering warm air, it's blowing cold, it might be because the condensate drain has frozen. Check the Pilot Light. And since even a modest-size home has dozens of outlets, the heat loss is significant. If the furnace burner itself is neglected, accumulated dust and grime can cause trouble igniting. It doesn’t seem possible, but a surprising amount of cold air blows in around electrical outlets. The fuel system, the burners, the fan and the ductwork. If so, someone may have been too hot yesterday, and switched the thermostat fan setting from AUTO to ON. This means that your electric heat strips are not coming on. If you haven’t done that yet this winter, call in an HVAC service expert to keep your system in top shape and prevent unexpected failures. If so, your blower may keep circulating cold air even after the burners fail to light and produce heat. But before you call for help, you might be able to do some simple troubleshooting and save yourself a little money by fixing it yourself. If you own a gas furnace, there are several potential things that can cause cold air to blow when you're expecting hot. You can try to follow your ductwork and check for leaks, you may even find something obvious and easy to fix. The last thing you want to find is that the furnace is not heating. If you’ve had the thermostat for a while, the battery might be low. During cold weather, you want to be sure that your furnace is blowing plenty of hot air. These components typically have a 3 to 5 year service life, so it's a good idea to keep a spare on hand for when it inevitably needs to be replaced. So 85-92°F feels cold to new heat pump owners. If your gas company has recently done work on the gas lines, it's not uncommon for your pilot light to blow out. If the pilot won’t light at all, you may have a faulty gas valve. But if you’ve set your fan to be “on” at all times, it’ll blow cold air during the furnace downtime. Fortunately, this is usually an easy fix. HVAC Preventative Maintenance Contracts: How to Find the Right One for Your HVAC Infrastructure. Is the Pilot Light lit? That may be a quick and easy fix. If this is the case, you can simply switch the setting from "on" to "auto" and your problem should be fixed. And if it's the dead of Winter, this can be a serious problem that needs immediate attention. If everything seems to work properly, and then your furnace blows cold air back and forth until it switches off, you may be faced with a furnace that has overheated. Your furnace may or may not be blowing cold air if your ductwork is leaking, but you may have noticed it more challenging to keep one or two rooms warm. If you have an older furnace with a continuous pilot light, the pilot may have gone out. If, after a few minutes you still experience the furnace blowing cold air, you may need to contact your HVAC contractor. Failure of the transformer that provides power to the thermostat can also … COVID-19 & Your HVAC System: Your Questions Answered, HVAC System Maintenance: 6 Tips for Heating Season, Essential Equipment for Commercial Kitchens: HVAC Make Up Unit. Your furnace blowing cold air could be caused by hot air escaping through holes in the duct work that carries the heat throughout your building. The thermocouple is a sensor that controls the gas valve and ignition. If not, the compromised air flow can cause your furnace to overheat, shutting down the burner. This is usually a simple fix, but you’ll need to call a technician to adjust or replace it. If your furnace blowing lukewarm air, give us call at 580-699-5662. Compromised flame sensor. This will eliminate the risk of freezing. This problem requires a visit from your HVAC repair technician. When an oil furnace blows cold air the problem could be the result of one of the following reasons: It may seem silly, but you'd be surprised at how many people's furnace problems are simply a case of running out of oil. The furnace will be more likely to pull in sediment from the tank, which can clog your air filter. Schedule service Troubleshooting tip #1: Check the thermostat If your furnace blows hot air sometimes and cool air at other times, … Depending on the type of burner you have, it isn't uncommon to experience any of the issues listed above. More cool air … The thermostat (ecobee 3 lite) is set to 69, the room is reading 67, and the fans seem to be blowing cool air. But if it doesn't light, or it won't stay lit, you'll want to check that gas is flowing to the pilot. If your fan is set to "on," your furnace will continue to blow cold air until the drain thaws. But, of course, there are many other possible causes. This usually arises if you haven’t changed your air filter routinely. A dirty air filter can block airflow over your furnace’s heat exchanger, which can cause it to overheat. In some cases, you may be able to fix the problem yourself. Here’s another possible DIY fix for your heater blowing cold air. Unfortunately, it isn't uncommon for an HSI to malfunction. Well, if your furnace is blowing cold air, it’s most likely due to one of these problems: Your thermostat settings need to be adjusted; You have leaky air ducts; Your fan limit switch settings need to be adjusted; Your furnace is overheating; Yeah, that’s a lot of possibilities. Clogged air filters could be causing cold air to blow out of your vents. Now your furnace will only blow warm air. All Rights Reserved. The oil from your fingers can cause permanent damage to the part. If you own an electric furnace and it's blowing cold air there's a few things that could be causing the problem. Changing your filter is a good starting point, but if the problem persists we have other options for you to troubleshoot. Electric furnaces pull air through a filter before it heats it. Mechanic's Assistant: Have you checked the coolant level? If not, call a professional. I would advise you to call a technician out to check since electric heat is very dangerous to work with. 6. But you need to know when to call in the furnace repair pros so you don’t have to spend unnecessary time in the cold and interrupt your business. Your ducts are usually in the attic and outside of your insulation, exposing them to the bitter cold. In other words; no vacuum means no ignition, which may be why you are experiencing cold air when you're expecting hot. In addition, there are a few problems that are unique to pilotless furnaces which you'll want to look into if the troubleshooting tips above don't fix your problem. Copyright 2020 Think Tank Home. Use a wrench or pliers to remove the pilot tube. Your thermostat has an ON and AUTO switch that runs your blower. Even worse, the furnace is blowing cold air! Troubleshooting a Furnace That's Blowing Cool Air. Have an expert inspect your ducts along with the furnace. 13 Common Causes. Check your thermostat. Your furnace may be blowing cold air because the pilot light has gone out. Have an expert inspect your ducts along with the furnace. This is a likely cause if your furnace blows hot air, then cold. AUTO ensures that the blower will run only when the furnace heats the air. If this is the case, someone walking by the burner could generate enough of a draft to cause the pilot to go out. An HSI or Hot Surface Ignitor is the most popular way to ignite a pilotless furnace. They are available in electric, gas and oil models. Try changing the batteries. You might be suprised to learn that one of the most common residential HVAC issues is the thermostat. Basically, the furnace isn’t lighting the fuel, meaning it can’t heat your home, either. Fortunately, there are specific reasons why your furnace may … If it does overheat, the safety control will shut off the burners, causing the fan to blow cool air through the house versus heated air. If your thermostat’s fan setting is set to ON, the furnace blower will constantly run even when your furnace isn’t heating the air. Use care not to touch an HSI when troubleshooting or installing a new one. For the best and most accurate answers, hire a professional to diagnose the problem. Have you changed your air filter lately? If this is the case, you'll first want to turn the gas valve that supplies the pilot light off. Faulty Thermocouple. Once the vacuum is created, the vacuum switch sends a signal for the furnace to ignite. If the vacuum does not occur, the furnace will not ignite. A heater blowing cold air could be a result of a leak in your ducting. If the filters are caked with dust, then it's likely the culprit behind your heater's malfunction. Is your furnace not blowing hot air? If the flame sensor is dirty, it will produce inaccurate readings which can cause heating issues. Depending on the age of your system and its model, you may have to manually relight it yourself or you may only need to push a button. Pilotless furnaces have been an energy-saving breakthrough for the home and commercial heating industries. Warm air is sent through your ducts when the thermostat says it’s needed. 11. But for the most part the temperature control switches are non-adjustable and are to be replaced if found faulty. If after refilling the tank your furnace doesn't turn on, it may be necessary to manually bleed and restart your furnace. A flame sensor that’s covered with grime or worn out can cause the burner to keep shutting off. Afraid it’s too expensive? Changing your furnace filter is an important part of caring for your HVAC system and it should be done, at minimum, every three months. The condensation must be removed from the system and if your condensate drain terminates outside your home, it can freeze. If you've recently had an electric power surge or any other power issue, the fix could be as simple as replacing a fuse or flipping the circuit breaker. You also don’t want to risk frozen pipes. But when it stops blowing hot air and starts blowing cold air, you know you have to find a solution. Even if your furnace is fairly new, things can go wrong that cause this unpleasant surprise. Excessive heat or exposure to water can damage the circuit board, which can cause your furnace to lose some or all of its functionality. If cleaning the pilot tube and ignition element doesn't solve the problem, and you continue to lose your pilot, the thermocouple may be defective. As your oil or gas-powered furnace heats the air, condensation is created. The reasoning here is simple: furnaces don’t pump out hot air nonstop. When the fan is on, the furnace will continue to blow, regardless of whether or not the air is being heated. When the condensate drain freezes, it causes condensation to drip back into your system and trigger a shutdown. The furnace blowing cold air, or there is no heat in the house. If you have a newer furnace with an electronic control panel, you may need to reset the system. If the switch is in the ON position, then the blower keeps running, even when the furnace is not heating. Your furnace’s limit switch, which specifically works as a safety measure, has turned your furnace burners off until the unit reaches a safe temperature. The “on” setting means that the furnace fan will be running even when the furnace itself is off. Ductwork is often installed in areas such as attics, garages or crawl spaces where there isn't temperature control. This could happen from a gust of air caused by someone working near the furnace. 7 Possible Reasons Your Home Heater/Furnace Is Blowing Cold Air. Check the Pilot Light. Seals breakdown, the constant pull of gravity, rodents, incorrect installation, and even age can play havoc when it comes to delivering hot air. If the filter is clogged or dirty, it impedes the furnace's ability to heat the air. If the furnace still blows cold air, call in a professional. If you did it yourself instead of calling a professional, you may have chosen a thermostat that’s not compatible with your heating system. If you know how and you’re comfortable doing it, you can try to relight the pilot yourself. When you get to your destination, you expect to walk into a toasty warm space. No matter how you travel to work, whether it’s by bus, car or train, your commute probably ends with a cold walk in the icy wind. Dust and debris inside the thermostat can cause it to malfunction. You’ll need a visit from an HVAC professional to make this furnace repair. Have you installed a new thermostat lately? This is especially common if you have an older fuel tank with a less-than-accurate fuel gauge. Consult an HVAC expert for advice. Furnace Blowing Cold Air? If it stays lit, you should be back in business. It’s normal for cool air to emerge from the vents at first because the furnace has to warm up. This is similar to rebooting your computer to fix a software glitch. Furnace Blowing Cold Air? This means the fan will run continuously without providing heat. The fan setting on your thermostat has two options, “on” and “auto”. If gas supply is interrupted for any reason, the gas furnace pilot light will go out. More often than not, electric heaters blow cold air when its filters are clogged, and that's why it's the first thing you should check. My 2016 Winnebago view electric furnace is blowing cold air, what could be the problem? If you choose to call a professional to do the job for you, this would be a good time to have your system inspected. You do not want the blower to stop if the burners are still lit. It's also possible that the furnace's pilot light isn't well shielded. If your furnace starts blowing warm but then quickly turns cold, the flame sensor may need attention. Ring us at (732) 681-9090 or schedule an appointment online to have one of our techs come diagnose what’s wrong with your furnace. This happened last night and this morning. Have your system professionally cleaned to take care of this problem. The thermocouple is a sensor that regulates ignition, and if it requires adjustment or replacement your furnace will blow cold air. Also, if your oil burner isn't functioning correctly you should check for a clogged filter. Have you checked for a leak in the radiator? Try replacing your furnace air filter and see if this improves air flow. When your furnace is blowing cold air your warm and inviting home can turn into an icebox in a matter of hours! Many times the problem can be resolved by restoring the thermostat to it's factory default settings. You can easily fix this problem by thawing the condensate, but you'll need to take long term measures to prevent the issue from happening again. If you do manage to relight the pilot but it keeps going out, a faulty thermocouple is likely causing your furnace to blow cold air. Salons & Spas: Improve Indoor Air Quality to Keep Customers Safe, COVID Prevention & Air Quality Technology Shown 99.9% Effective. Wait a few minutes, then restart. Over time, the changing temperatures wear on all sorts of things and your ductwork is no exception. In fact, the problem may be as simple as changing your filter! There's a lot of issues that can cause your ducts to leak. After checking that your fuel level is adequate and your filter is clean, the next area to check is the flame sensor. Your body temperature is around 98.6°F (everyone’s body temperature is slightly different, but that’s the average). If this doesn't resolve your cold air problem it could be the themostat itself, but before calling a professional, we recommend trying the other troubleshooting suggestions first. Details Your furnace can then trip a high limit switch which will, in turn, cause the furnace burners to shut off so that the heat exchangers don’t crack. To do this find the gas line and make sure that the gas valve is parallel with the pipe. As an Amazon Associate we earn from qualifying purchases. I checked the system monitor data. The thermocouple is a sensor that regulates ignition, and if it requires adjustment or replacement your furnace will blow cold air. When this is the case there's a good chance that the material will degrade and begin to leak. Leaky ductwork can cause serious issues for your heating system. Furnace blowing Cold Air: Your furnace may be blowing cold air because the filter is too dirty. If you get a blast of cool air when you first turn on the furnace, but after a couple of minutes the air feels warm, that is nothing to be concerned about. IAQ and Mold in NYC Buildings: Are Kids at Risk? Your furnace blowing cold air could be caused by hot air escaping through holes in the duct work that carries the heat throughout your building. Here in the New York City area, we’re all pretty tired of the cold weather by now. In most situations, it's best to enlist the help of a professional to fix this problem. If your furnace ran out of fuel, or was simply low on fuel, this could be your problem. The first thing you should check is the fuses or circuit breaker. Read on to learn the 13 most common reasons for your furnace blowing cold air and when to call for a furnace repair. The best thing to do is have an HVAC specialist route the condensate drain into your sewage drain. If your pilot light did go out, try to relight it. Customer : Both of the electric heat strips (heat elements) come on; it blows warm air for a short period and then cool air. If you notice your furnace only blows cold air on occasion but your home is still maintaining its temperature than this may be simply a setting on your thermostat. Before calling for repairs, check your fuel level. Your furnace may be blowing cold air because the filter is too dirty. Another telltale sign is if your utility bills are higher than they should be based on use. In this case, you could feel cold (or non-heated) air blowing through your vents because the system is … Turn the gas valve to the "on" position, and try to light the pilot again. There are four main components of a furnace. To mitigate carbon monoxide and puff backs, an internal motor kicks on and creates a vacuum just before the burner engages. A dirty air filter blocks airflow over the furnace’s heat exchanger, causing it to overheat. That’s why the furnace is not blowing hot air. Or, if your system has not been cleaned in a while, a valve could be stuck due to dirt and debris. Next, use fine-grit sandpaper to remove any oxidation from the tip of the pilot, and reattach the pilot tube to the furnace. So, how do you know which problem is causing your furnace to blow cool air? When this happens, … Many of the causes of furnace problems can be prevented with regularly-scheduled cleaning and maintenance. These are the most common reasons a furnace will blow lukewarm air. But you might want to consider calling a professional HVAC service who has the knowledge, tools and experience to find and repair the problem. They may even need to run a static pressure test during their assessment. If your blower does not shut off and it’s not blowing cold air, then that means the burner is still lit. Hi all, I think our thermostat/furnace isn't working properly. If you have a newer furnace with an electronic ignition, such as an intermittent pilot or a hot surface ignition, your system may need adjustments or replacement of failed parts. Mechanic's Assistant: What is the make/model of your '16 RV? If the filter becomes clogged, the unit can start to overheat and cause the burner to shut down. Check to see if one of these troubleshooting tips fixes the issue. Although you can do this yourself, we recommend calling a professional as there may be another underlining problem. Solution: Turn your thermostat’s fan setting to AUTO. Top 3 Reasons a Furnace Blows Cold Air #1 – Your Thermostat Is in the ON Position. Have your system cleaned and checked by an HVAC professional. A dirty air filter blocks airflow over the furnace’s heat exchanger, causing it to overheat. Heat Pump Troubleshooting: 3 Common Problems and Solutions, The Rewards of Giving Back: Arista Team Rebuilds a Home in Puerto Rico, Commercial Refrigeration Service & Repair. Count your blessings that this time you avoided an expensive furnace repair. If you have an oil-fired furnace, you may be out of fuel. If you know how, you can clean or replace the filter yourself, but it’s messy and not as easy as an air filter so you may want to leave this job to the pros. A furnace that blows cold air could also indicate that it is overheating. If cleaning the pilot tube and ignition element doesn't solve the problem, and you continue to lose your pilot, the thermocouple may be defective. In some cases, a malfunctioning thermostat may require adjustment or replacement . The HSI features a cobalt element that's prone to cracking. Then, use a pipe cleaner or other small brush to remove any clogs within the supply tube. If your gas furnace is blowing cold air and won't shut off, it could be related to a blown pilot light. Consult your users manual for directions on restoring the settings for your specific unit. Check the owner’s information for your furnace to see if there should be a blower delay after the burner kicks on. The best service providers can customize a plan for your needs and your budget. The engine is off, and I'm running the furnace while plug in electric. So, if you have a tripped breaker, the furnace may stay on however, the air can’t warm up because the gas burner can’t ignite. The flame sensor itself is relatively easy to clean, but many homeowners are uncomforable working on their furnaces. It restricts the airflow in and out of your furnace, which can cause this issue. When the furnace is turned on after a certain period, whether it be days, weeks or months, turning on the system does not mean that warm air will automatically begin to pass through the vents. This too can cause your heater to blow cold air. Learn more from our free guide: HVAC Preventative Maintenance Contracts: How to Find the Right One for Your HVAC Infrastructure. If you have a washable air filter (which I wouldn’t recommend), then ensure that … Your furnace may be blowing cold air … The “on” option is exactly how it sounds. The pilot light is another common culprit of gas furnace problems. It’s a simple fix; just relight the pilot. (That’s where a tech will start first, so you should as well.) As soon as the furnace cycles back on the air will warm up again. Do you have thermostat wars going on in your office? If the gas is on, but the pilot won't light or stay lit, the pilot tube or orifice may be dirty. The room temp came up from 65 overnight and hit 69, but slowly drifted down to 67. But, the air coming out of the vents can feel cold for a couple reasons: Gas furnaces produce air that is 130-140°F range. If your furnace seems to be blowing cold air, it could be a problem with the ignition system. These Common Issues May be the Reason, AC Evaporator Coils: Everything You Need to Know, AC Compressor Not Working but Fan is Running, Evaporator Coil Leak: What You Need to Do, Looking for A Portable Air Conditioner That Doesn’t Need A Window, Why Your Furnace is Short Cycling and What to Do About It, Best 50 Gallon Electric Water Heaters: Our Top Picks. The Pilot Light is Out Symptoms.