Troubleshoot a Furnace Blowing Cold Air

furnace-troubleshooting-no-hot-air

If your furnace happens to be blowing cold air when it should be heating your home, there are a few troubleshooting tips you may want to try out before calling in for repairs. Below, you’ll find the most common reasons for cold air coming out of your furnace and what you may be able to do to rectify the situation on your own.

 

Check the thermostat
Actually, the first thing you may want to check if the furnace isn’t working properly is the thermostat. Be sure that it’s set to heat and not cool. As it’s possible that somebody has accidentally changed the setting. To test the thermostat, you can set it for five degrees above the current room temperature to see if the furnace starts to work. While you’re checking the thermostat you should make sure the batteries don’t need to be replaced and blow out any debris and dust in the unit. Remember, if the thermostat’s fan is set to the on position, the blower will run constantly, but won’t be eating the house. The thermostat setting should be place to heat or auto.

 

Check the air ducts
If the majority of your home is receiving warm air, but there are a couple of cool spots, you should have a look at the air ducts. Be sure that all of the ducts are fully open as these control the flow of air. If the ducts are open and there’s still no warm air coming from them the air could be escaping through holes, cracks or gaps. If the ducts are leaking it means the warm air isn’t making it to the room and this will cause your energy bill to rise. In addition, dust could be sucked up into the ducts and this will reduce the air quality in the home. If you find any leaks in the ducts you may be able to use a sealant to fix them.

 

Change the filter if necessary
A dirty filter can easily block the return air flow from getting to the furnace. If the filter is dirty it can reduce the amount of warm air which should be blown back into the home. This will naturally mean you’re not getting the heat you should be through the air vents and things can cool off pretty quickly. The furnace’s safety feature could also shut the furnace down because of a dirty filter since the heat exchanger may overheat as it works overtime to heat the home. In addition, soot may build up in furnace’s heat exchanger and this will reduce its effectiveness and possibly its lifespan. It’s recommended that the filter be checked at least once every three months and changed if it’s dirty. Before changing the filter though, be sure to shut both the thermostat and furnace off.

 

Close the blower motor panel
You should also make sure the blower motor panel is properly closed. It’s possible that it isn’t shut properly and if this is the case the furnace won’t run due to its built-in safety device.

 

Check the pilot light and gas valve
If the gas furnace is blowing just cold air it’s possible the pilot light has gone out. If it’s out, relight it and see if it stays on. If it doesn’t, it’s always possible that somebody has turned the gas valve off of the furnace and has neglected to turn it back on. Without gas, the furnace simply has no fuel to burn and heat up the home. If the gas valve is on the pilot light could be dirty. If this is the case, clean it off so there’s enough gas getting through to it. If the pilot light goes on, but then extinguishes itself, there could be a some wrong with the thermocouple and it may need to be replaced or adjusted.

 

If there’s anything above that you’re not comfortable doing or simply don’t have the time to check, please feel free to contact us at Lloyd HVAC Services. We’ll be glad to send one of our specially-trained contractors out as soon as possible to give you a hand with the furnace and make sure you’re getting heat when you need it.  We also offer affordable annual maintenance agreements that will keep your HVAC unit running smoothly all season long, all at a fraction of the price of an average repair call.