Why Is My Furnace Blowing Cold Air?

We are dealing with cold temperatures in Charlotte so having our heating systems working well is paramount to our staying warm and comfortable, This is definitely not the time you want a problem with your furnace. One of the more common service calls we receive at MTB is from people complaining that their furnace is blowing out cold air. There are different reasons this could be happening. Below are listed three common causes that you can fix at home.* Thermostat setting is turned to ON- Does your furnace blow cold air all of the time? Is the blower running constantly? A technician would always start by checking your thermostat. If the fan is set on the ON position, your blower will run constantly even when your furnance is not heating the air. If this is the case, simply turn your thermostat to the AUTO position.
*Overheated furnace- Did your furnace blow hot air and then cold air and then stop blowing air completely? If so, It’s possible that your furnace has overheated. If this happened, the limit switch, which is a safety device has turned your furnace burners off. Your blower is continuing to blow in order to cool the furnace down to a level considered safe. So why did your furnace overheat? The most common reason is a dirty air filter. A dirty filter blocks airflow which causes the furnace to have to run longer and work harder. This leads to overheating. Change the filter and see if this fixes the problem.
Pilot Light has gone out. If your furnace is blowing cold air your pilot light may have gone out. Check your furnace to see if this has happened. If so:
1) Try to re-light the pilot. If the flame stays on your problem is solved.
2) If the pilot won’t light, check to see if gas is flowing into your furnace. Is your furnace gas valve swith in the ON position?
3) If your pilot will not stay lit, there’ a problem with your therocouple which is the copper rod that you see the flame hitting. This may need to be adjusted or replaced, but it is a job for an experienced technician.
We hope this will be helpful to you and save you the expense of a service call. However, MTB Heating and Air is always available to help you out with any HVAC problem you may have. Right now, we are offering $30 off on any repair, so give us a call and we will have your system up and running at peak efficiency quickly and affordably.