If you have a gas furnace and it’s blowing cold air, there could be a number of different reasons for this behavior. Many of these issues can be easily addressed by you without expert assistance from a trained professional. In this article, we will look at some common causes, but if you don’t feel confident about dealing with your gas furnace, give us a call, and we will be happy to help.
Check the Furnace Power
This is the simplest issue to deal with and the first thing that you may want to check. It’s important to establish that the gas furnace is receiving adequate power to function. Check the fuses and circuit breakers to ensure that the emergency power switch hasn’t been turned off accidentally.
Carry Out a Reset
If the furnace has a reset button, you can press it to see if the furnace power up. The reset button is usually a red button located on either the front, back or sides of the furnace. If the reset works, you will soon notice that there is heated air cycling through your home. Carrying out a reset is often the only thing necessary to get your furnace up and running again quickly.
Check the Thermostat
If you’re getting an uneven heating performance, it’s a good idea to check out the thermostat. Make sure that your thermostat is set to heat and not cool and the fan should be set to automatic. The temperature should be high enough to get the furnace to trigger and emit some heat. If the thermostat is set correctly, make sure that it’s receiving power by checking the fuses, circuit breakers, and batteries. The thermostat interior should be clean, dirt and dust can cause the unit to malfunction. If these fixes don’t work, the thermostat may need to be adjusted or replaced by a professional.
Change the Filter
One of the most common causes of a furnace failure is a dirty air filter. When the furnace filter is dirty, the flow of air is impeded, and this can cause overheating issues. If you think that the air filter is causing the problem, change it and press the red button to reset the furnace. It’s a good idea to change your air filter once a month, and this will help your furnace to work more efficiently. If a dirty air filter is ignored, it could cause damage to your furnace that will be expensive to fix.
Examine the Door Cover
If you’ve recently changed the air filter and you have a cold air issue, you may have left the door cover open. The furnace door needs to be fully closed for the furnace to work effectively. Simply shut the door cover firmly, and this should quickly fix the problem.
Check the Pilot Light
An older furnace may have a standing pilot light, and this could have gone out. The first thing you need to do is check through the pilot opening to see if the pilot light is out. If it is, turn the gas valve to the off position and then wait at least five minutes. If you have a reset button, turn the gas valve to pilot and hold up a naked flame to the pilot opening while you hold the button for around 30 seconds. The pilot may light immediately, or it could take a few attempts. If you need to try again repeat the procedure, but hold the reset button for 45-60 seconds instead. As soon as the pilot light is lit, you can turn the gas valve back on. If your pilot light will not stay lit, there could be a problem with the ignition system or the thermostat. If this is the case, you will need to call on an HVAC professional for expert assistance.
Check the Heating Registers
If you have too many heat registers closed in your home, it can cause a heat build up in the furnace. This will force some air out of any duct leaks, and the blowers will be forced to compensate for the additional pressure. Blocking heating vents will cause your furnace to work much harder and for longer periods that it’s designed for. This build up of air pressure in your ducts could cause airflow leaks and make existing leaks far worse. Heating experts recommend that at least 80% of the heat registers should be kept open to avoid these issues.
A Dirty Flame Sensor
The flame sensor is necessary to safeguard your furnace against unsafe fuel burning. If the sensor is dirty, it can cause the furnace to work erratically, and it will need to be cleaned to restore functionality. The flame sensor is typically a rod that’s located somewhere near the back of the furnace in the path of the burner. Turn of the furnace power supply, remove the sensor and then scrub it gently to remove the dirt and dust. Then just reattach it and restore the power to the furnace.
There is a Gas Leak
If there is any suspicion that a gas leak has occurred, it should be dealt with immediately. If you can smell gas in your home or around the furnace, don’t light matches or turn on switches. Shut off the gas valve by turning the valve until it’s perpendicular to the supply line and evacuate the home. There should also be a gas supply valve located near the gas meter, and this should be turned off with a quarter turn using an adjustable wrench. Then call your gas utility and don’t return to the home until you get the all clear.
As you can see, many of these gas furnace issues are a simple fix for anyone with little to no DIY experience. Following these tips should correct many minor issues and get your furnace producing heat again quickly. If you find that you cannot identify and correct the problem, it’s time to get in touch with an HVAC professional.