Count your blessings that this time you avoided an expensive furnace repair. This is sometimes easily solved by resetting the system. Wait a few minutes, then restart. 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. How Does Workplace Ventilation Impact Employee Productivity? If your furnace overheats, it could end up blowing cold air. Have you installed a new thermostat lately? If the leaks aren’t excessive, a professional may opt to repair single leaks. When the filter is clogged, ignition can be affected and the result is your heating not blowing hot air. Most furnaces have safety features that will automatically shut off the burners when it senses the furnace is overheating. If your furnace continues to blow cold air then you should check if you have a two-stage furnace. So, once a heating cycle ends and the furnace burners cut off, the fan continues to blow. A dirty air filter can block airflow over your furnace’s heat exchanger, which can cause it to overheat. A furnace that blows cold air could also indicate that it is overheating. Check the furnace’s air filter. And when the blower slows down, it can’t push as much cool air over the heat exchanger, eventually causing it to overheat. Pilot Light. All Rights Reserved. Do you have thermostat wars going on in your office? If your fan only runs when your furnace is heating the air, then you’re much less likely to experience your furnace blowing cold air. Your furnace is a controlled fire burning inside your home. The fan setting on your thermostat has two options, “on” and “auto”. So here’s the situation: It’s a chilly night in Phoenix and you turn the heat on, expecting some warm relief. When a heating cycle begins and your air handler turns on, that cool air will blow out of your registers before warm air does. 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. Or, if your system has not been cleaned in a while, a valve could be stuck due to dirt and debris. A furnace that isn’t getting fuel will not ignite and will blow only cold air. If you’ve had the thermostat for a while, the battery might be low. If your furnace fan is set to ON, the fan runs continuously, whether or not your furnace is producing heat. Other thermostat issues. Normally, this switch should allow the furnace burners to warm up completely before turning the fan on and should keep the fan running just until the burners cool off slightly (to prevent damage or overheating). Or the gas line isn’t supplying enough gas to your furnace. If not, call a professional. What Can I Do If My Heater Is Blowing Cold Air? 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 lukewarm air coming out of your furnace can also be the result of leaky air ducts. It is usual for cold air to enter the heating system until it is warm, and then for warm air to continue to blow after the air heats up. This usually results in a confused homeowner who thinks the cold air from their vents means there’s a problem with their furnace when really their HVAC systems are responding properly. From dirty air filters to broken thermostats, these are the most common causes of problems. A furnace limit switch uses sensors to read the air temperature inside the furnace and trigger the fan so that the fan only turns on when the air is hot enough and automatically turns off after the furnace quits. But that fan has two modes of operation: ON and AUTO. When a Furnace Blows Cold Air: Troubleshooting Your Heater It’s time to re-explore an issue that we get called about a lot during this time of the year—a furnace that’s blowing cold air. If the furnace is cold, it cannot heat the air being propelled outside. Otherwise your electric heater or gas furnace will not turn on. If you have an older furnace with a continuous pilot light, the pilot may have gone out. So you’ve turned on your furnace, but it’s giving you the cold shoulder by blowing cold air. Now let’s talk about an even more common reason a furnace might blow cold air: you’re using the wrong fan settings. 1. Translation: When your fan limit switch is set correctly and is working properly, you should never feel chilly air coming from your vents. You’ve got three basic options. Major duct problems. You see, a clogged filter restricts the amount of cool air that runs through your furnace’s system and causes the unit to quickly overheat and shut off. When your furnace isn’t running, the air in your ducts cools down. If this is the case, you can simply switch the setting from "on" … Luckily, it’s usually very easy to fix, and problems can also be prevented with … Need a tech ASAP? They may be able to adjust the settings so that the fan won’t blow cold air into your home. Why Is My Furnace Blowing Cold Air? Consult an HVAC expert for advice. We’ll explain each of the problems above, how you’ll know if that’s your particular issue and what you can do to fix it. In some cases, you may be able to fix the problem yourself. Well, it could be multiple issues; some of them you can solve yourself. What’s wrong? Furnace blows cold air: This article describes what to check if the warm air heating blower fan delivers intermittent cold air into the occupied space, or if the furnace cycles between blowing warm air & cool or even cold air into the building.. 6. Have a technician inspect your air ducts for leaks, Have a professional inspect the fan limit switch, Your thermostat settings need to be adjusted, Your fan limit switch settings need to be adjusted, Your thermostat fan button is positioned under ON or set to COOL, Your thermostat is still set to COOL not HEAT, Your thermostat fan setting is set to ON not AUTO, Your heating and cooling systems struggle to reach your desired temperature, You have higher-than-normal utility bills, Certain rooms or areas are stuffy or don’t cool/heat properly, You see ductwork with kinks, holes or loose connections, The air coming from your vents is first chilly, eventually turns warm but then gets chilly again before the fan cuts off completely between heating cycles. Make sure your thermostat is set to HEAT and your fan is set to AUTO. For safety the air being propelled outside grime or worn out can cause it to.. Pushed into your home, either and we ’ ll need to for. 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