If the fan limit switch malfunctions, the blower might continue to operate even when the furnace is not
A furnace blowing cold air could be the result of a leak in your ducting. Over time, the changing temperatures wear on all sorts of things, including your ductwork. In fact, it's rather normal for ductwork to develop leaks over time. When ductwork has a leak, cold air will enter a duct and blow into your home.
The most common reason a heat pump is blowing cold air through your air vents is defrost mode. This is a safety feature to melt frost and ice within the system. During defrost mode your heat pump made switch modes to heat up the outdoor coils. Indoor temperatures will fall because the system is briefly in cooling mode.
Yes, you should turn your heater off if it's blowing cold air to prevent potential damage to the system. Running a malfunctioning heater can strain the components, leading to more significant issues and increased energy usage.
You Have Cold Air Blowing Out The Vents When The Heat Is On Because of a Dirty Air Filter. Hiding in the filter of your heating system is dirt and debris. If you aren't cleaning it regularly, this will accumulate over time, leading to problems with your heating system's efficiency.
Most modern thermostats will have a clearly marked reset button inside the panel. It's usually small and recessed, so you might need a pointed object like a paperclip to press it. For those wondering specifically how to reset air conditioner thermostat models, the process is generally the same.
It May Be Blowing Relatively Cooler Air
Given that the ideal thermostat setting is at 68 degrees, blown air at 90 degrees is actually warmer than what is needed for heating. However, it is cooler compared to the average body temperature of 98.6 degrees, which makes it feel cool, and is often mistaken for cold air.
A propane furnace or oil furnace blowing cold air might indicate a low or empty fuel supply. And, a clogged oil filter can also cause an oil furnace to turn on and blow cold air. If you suspect a fuel supply issue with your natural gas furnace, it's best to contact a qualified professional.
Simply reset the thermostat to AUTO. What causes the heater fan to emit cold air is the ON switch allows the fan to operate even when heat isn't required to maintain temperature control. Checking the pilot light and seeing if it is out could be a quick fix also. If the pilot is out you can try relighting it.
Check Furnace Air Filter
A dirty air filter hinders air movement through the furnace. This raises temperatures inside the furnace, and the limit switch shuts heating cycles down if the unit becomes too hot. If you have a dirty filter, replacing the filter typically stops cold air from blowing.
Four common reasons there isn't enough hot air blowing out of your vents are: A Vent is Blocked. The Air Filter is Clogged. Leaky Ductwork.
Choose "AUTO" for energy savings and "ON" if you want constant air circulation or improved air filtration. Temperatures can soar or plummet depending on the time of year. Throughout the year, it is important to have reliable heating and cooling systems in order to keep your home supplied with cool or warm air.
If your furnace is blowing cold air in your home, this is a sign of an issue with the flame detector, gas supply, air filter, pilot light, or condensate lines. Many of these issues are able to be easily solved on your own by sanitizing or replacing components in the gas furnace.
The most common cause of a furnace that blows cold and warm air intermittently is a thermostat fan setting that is set to ON. Furnaces run in heating cycles and only produce hot air for short bursts of time. When your fan setting on your thermostat is set to AUTO, the fan only blows when the furnace is heating the air.
Change the furnace filter on a regular basis to prevent airflow problems. Closed or obstructed vents can also cause it to feel like the furnace isn't making enough heat, because not all of its hot air makes it through the vents into your living areas. Check all vents to make sure louvers are open.
Possible causes include a broken thermostat; the thermostat being set too low; an out pilot light; a blown fuse or circuit breaker; a closed gas valve; or electronic ignition problems.
Troubleshooting Tips For Furnaces Not Blowing Hot Air
Inspect your thermostat's fan settings to see whether they're “auto” rather than “on”. Ensure your thermostat has not been set to a lower setting by someone else. Check your thermostat's batteries and replace any that are exhausted or defective.
Poor circulation
Underlying arterial disease could be causing inadequate blood circulation, making it hard to maintain core body temperature, especially in your extremities. Smoking affects temperature regulation in a similar way by causing blood vessels to constrict.
The Furnace Filter is Dirty
An overly clogged dirty filter will limit air flow to your furnace and could cause it to overheat and turn off. The heated air has nowhere to go, and then the furnace blowing cold air is all you're going to get!
Switch the thermostat to the off position. Locate the breaker that powers your HVAC system and turn it off. Wait 30 seconds and turn the breaker back on. Turn your thermostat back on and confirm it has reset properly.
Press the reset button. Most models require you to hold the button down for 3-5 seconds before releasing. Restore power to your AC. Restore power to the unit at the circuit breaker, and make sure the unit is set to “on” and your thermostat is set to “cool.”