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A furnace is supposed to keep the space warm in winter, despite the frosty cold outside. Sometimes, the furnace seems to be working normally, but the air it is blowing is cold instead of hot. It exacerbates the chills instead of eliminating them. This issue is not because of a technical default during manufacturing or due to a mistake in furnace installation service. That’s why there is no need to be frustrated.
In this blog, we are going to uncover the 14 common reasons that cause the furnace to blow cold air. We will also discover the practical tips to fix every issue, restoring a normal working furnace.
This is one of the most common issues often seen at both residential as well as commercial facilities. The issue arises if the fan is set to “ON” and not to the “AUTO” setting. This setting dictates that the fan blows air even when the furnace is not working. The result is the cold air from the furnace.
Tips to Fix It: Set the fan setting to “Auto” and the thermostat to “Heat”.
At startup, furnaces often blow cold air until the heat exchanger gets warmed. This is a very short period and often lasts for only a few minutes. As soon as fuel combustion is initiated and the heat supply is provided to associated components, the blown air gets warmer and warmer.
Tips to Fix It: It doesn’t need any troubleshooting steps, as this issue automatically disappears after a few minutes.
When the air filters are clogged, blocked, or dirty, the furnace blows cold air. This is because clogged filters restrict the airflow. As a result, the furnace becomes overheated, and it automatically shuts off operations. On the other hand, fans keep on working, and that’s why cold air is blown because the furnace is no longer working to produce heat.
Tips to Fix It: Carefully replace the air filters via a DIY method. This process can be messy; that’s why calling a professional is often recommended.
This issue is more prevalent in older furnaces that use gas as a fuel source. The pilot light is responsible for igniting the fuel source. When the pilot light is out, the flame is extinguished, and there is no heating at all. This may happen because of the air or might be due to some other reasons. The frequent extinguishing indicates the involvement of complex issues.
How to Fix It: Relight the flame carefully according to the manufacturer’s guide. If the flame is out again and again, call HVAC professionals for furnace repair service.
This issue is identical to the extinguished pilot light as discussed above. The difference is that the electronic ignition system is in modern furnaces, while the pilot light is in traditional ones. When the ignition system fails, the burner won’t light up. But again, the blower will keep working, blowing cold air through vents.
How to Fix It: The Ignition system requires certified professionals to repair or replace it. Trying a DIY method is not safe.
If the fuel is not being supplied to the combustion chamber, the furnace is unable to produce heat. This may arise in case of less than the required fuel supply or partially closed valves that allow fuel to the combustion chamber. In both cases, the furnace is non-functional temporarily, but the fan is working, blowing the cold air from the vents.
How to Fix It: Make sure the right fuel is being supplied in enough quantity.
A furnace can be overheated due to many reasons. Some of the common ones include clogged air filters, blocked vents, and restricted airflow. In all these cases, the furnace stops working, but the blower fan continues its operation, blowing cold air.
How to Fix It: Resolve the primary cause that is making the furnace overheated, and this issue will automatically disappear.
The flame sensor signals the furnace that the burner is lit. When this flame sensor is compromised or covered with grime, it can’t perform its function well. The result is that the furnace shuts off the gas as a safety precaution. The blower will, on the other hand, blow cold air through the vents. That’s the reason it is recommended to use a high-quality flame sensor at the time of business heating installation.
How to Fix It: Fixing the faulty flame sensor requires dealing with both electric and gas components. That’s why it is recommended to hire a professional for this purpose.
If the ductwork is leaky or contains significant holes, it is a primary source of wasting the warm air. As a result, the conditioned air is wasted into the crawlspaces, basements, and unnecessary areas of the site. Sometimes the colder air gets into the ducts via these cracks and fractures. Due to all this, cold air reaches the blower fan, which circulates it into the space.
How to Fix It: The best and only option to resolve this problem is to seal the ductwork or replace it all. For sealing, a professional inspection service is recommended to find the areas with leaks.
The size of the furnace matters the most. It is essential to prevent commercial heating repairs. An oversized furnace heats too quickly and immediately shuts off. On the other side, an undersized furnace struggles to meet the heating needs of the business site. Both scenarios result in complaints of cold air from the vents.
How to Fix It: Always choose a furnace for your Pennsylvania or New Jersey business after a manual J load calculation, not the guesswork.
Cracked heat exchangers are very hazardous. They are not limited to the cold air complaints only. They are also associated with very risky carbon monoxide poisoning. Modern thermostats have many integrated safety features that automatically shut off the burner after CO detection. The result is no warmth, a working fan, and cold air blown off.
How to Fix It: It involves serious safety and health risks. That’s why calling a professional is recommended without delay.
Most of the furnaces have a lifespan of 15-20 years. After this period, the components are damaged, and the system loses its efficiency. It results in less heating production compared to the comfort demands of the site. And hence, the blower has to distribute cold air through the zones.
How to Fix It: Hire a professional company for HVAC services in PA and get a new heating appliance installed in your business's space according to your preference.
Modern furnaces are controlled by an electronic panel. Occasionally, there arises a glitch in this control panel. It may cause multiple issues, including a temporary pause in furnace operation while the blower keeps blowing the cold air from the vents.
How to Fix It: To fix this issue, switch off the control panel, wait for a few minutes, and switch it on again. It will reset the panel, and all functions are restored to normal. If the problem persists, call your HVAC professionals.
Condensation often occurs when hot and cold air are mixed. That’s why most of the HVAC appliances contain condensate drain lines to prevent buildup. If the condensate line is clogged, the sensors may not get the signal to produce heating, and that’s why cold air is blown by the fan.
How to Fix It: The only way to restore normal furnace operation is to unclog the condensate line. Calling a professional is a better choice as DIY might not yield satisfactory results.
A furnace can sometimes start blowing cold air from the vents. This can be due to a variety of reasons. The best you can do is to check the components and find the actual problem that is leading to this issue. Once identified, proceed towards fixing it step-by-step, according to the manufacturer’s guide. For sensitive issues involving health or property risks, call your local HVAC professionals.
In Pennsylvania and New Jersey, Lehigh HVAC is the leading provider of HVAC services. When you notice cold air from the vents, contact us directly. We will inspect the problem and fix it in no time. And for payment, you have a fantastic option of GreenSky 0% financing. Contact us at 484-961-7044 for a free consultation.
