Furnaces can be intimidating, more so when they aren’t working. The good news is that many issues can be taken care of on your own. An estimated quarter of all service calls can be avoided with an easy fix that will cost little or nothing. Let’s explore some of the common issues that can cause furnace malfunctions.
Gas Furnace Troubleshooting When Not Turning On, No Heat, Won’t Ignite Etc
1. Make sure the thermostat is on. You need to see if the thermostat is telling the furnace to come on. Newer programmable thermostats can be confusing and more options can lead to more things going wrong. After you make sure it’s on, check the temperature setting and compare it to the temperature in the room. Then set the temperature five degrees higher than the temperature in the room to see if will force their furnace to kick in. Check the wires to see if there are any breaks and splice them back together if needed.
2. Check the breakers and shutoff switches. If all that’s needed is for a breaker to be switched back on, you’ll save money on the service call. A lot of the time this is all that’s wrong. Look for a switch near the furnace that looks like a light switch. No matter the age of the furnace, they all have one. There’s also a pushpin switch under the blower motor that needs to be checked.
3. Replace filters. The most common problems with furnaces is a dirty filter. Airflow is restricted when filters are clogged with dust and debris. This causes the heat exchanger to work harder, overheat and shut off too quickly. If you can see that the blower is running but there isn’t any heat, the filter needs to be replaced. Check with the owner’s manual to get the right filter and learn how to replace it.
4. Check to see if the gas is on. The gas switch could have been turned off accidentally. Just trace the gas line back to the furnace and see it it’s off.
5. Check the chimney flue. Turn the furnace off and with the thermostat turned all the way down, take the duct apart and check for blockages. Remove any blockages and reassemble it the same order you took it apart.
6. Clean drain lines. During the heating season, furnaces can drain off several gallons of water each day. If the lines become restricted, it can cause the furnace to shut down. Use a bleach and water (25 percent bleach) to clean the lines.
7. Inspect ducts for leaks or blockages. If your furnace is running, but there are rooms that are still cold, you should check the registers to see if they’re open. Then you can check any ductwork you have access to for gaps and seal them. If you see handles that are protruding from the ductwork, make sure they’re open as they are dampers for air conditioner bypasses.
8. Check intake and exhaust vents for debris. If your furnace vents to the outside of your home, then you’ll need to look for blockages. This can be leaves, grass or dirt. If its ice, you will need to contact a professional, as there could be a bigger problem somewhere in the system.