When your furnace unexpectedly goes out, try these furnace troubleshooting tips before reaching for the phone. You may be able to restore the system yourself, eliminating the discomfort that an increasingly chilly home causes.
- The thermostat. Verify that the thermostat is set to heat and the temperature setting is above the air temperature by a few degrees. If in doubt, set the thermostat four degrees higher than the room’s air. Replace the batteries if it’s not hard-wired.
- No power. All gas furnaces have a switch located in the front of the blower compartment. Reset it by pushing it or moving it to its “on” position. If it doesn’t start soon, check the circuit breaker. If the breaker tripped, reset it. If the circuit breaker trips soon after resetting it, call your HVAC contractor for professional help.
- Dirty air filter. Almost all gas furnaces have safety switches inside them that turn the furnace off when there isn’t enough air flowing through them. When furnace troubleshooting, look at the air filter. If it’s covered with dust, it won’t allow enough air into the blower compartment and if it continues to run, the components would build too much heat, creating a safety hazard. During the winter when the furnace runs routinely, it’s a good idea to check the air filter monthly and change it when it’s dirty.
- Blocked flue. If the flue vent is blocked, the furnace will automatically shut off. If you can’t access it easily, call your HVAC contractor.
- Ignition problems. Diagnosing ignition problems is fairly easy with a furnace that uses a standing pilot light. If the pilot goes out periodically, clean the thermocouple and the pilot. If the pilot still goes out, the thermocouple may need replacing. If your furnace has electronic ignition, it uses a furnace ignitor. This part uses a filament that creates a spark to ignite the fuel. They can and do wear out and should be replaced by an HVAC professional.
For more tips about furnace troubleshooting, contact Apollo Home Heating, Cooling and Plumbing, serving homeowners in the greater Cincinnati area since 1910.
"Ernie & Mike did a superb job on my new furnace and A/C installation. Despite having more than a day’s work to do, they came in and stayed until the job was done. They were organized, efficient, and protected the rest of the house well. Got both furnace and A/C installed the same day. Ernie was courteous, informative, and clearly knew his job better than anyone I’ve encountered before. The units look so good guests now get The Tour of our new system. Apollo is clearly not a fly-by-night company. I would recommend them to anyone in need of a new furnace and/or A/C."
- Jerry A.
"I called Apollo because of a water leak I thought I had in our upstairs shower going into the kitchen. Robbie came and assured me everything was fine & looked at all the other plumbing. He ended up changing a few pipes for our washer & clearing a drain. He was very nice & knowledgeable with all my questions. I ended up signing up for the care plan & was very happy with my service."
- Cassandra B.
"The team at Apollo exceeded my expectations. As a business owner, my attention to the details and commitment to providing excellent service is high. From the sales rep. to the installation team, everyone’s performance was outstanding. For example, the installation team went to great lengths to protect our floors, placing floor runners and across the wood floors and up the stairs. They even were spot washing walls upon their departure. I highly recommend this company."
- Randy B.
"We scheduled an estimate AND a tune-up. We knew something was wrong with our furnace, but hoped we could make it through the rest of the season. Upon telling Bill what our furnace was doing, he warned us immediately what the possible outcome was going to be; a cracked heat exchanger. He watched the flames roll backward, tested carbon monoxide levels, which were so high they meter’s last reading was 5,600 before saying “high”. He immediately shut it down, tagged it, and explained that with levels that high and children in our home he wanted off right away. He continued his inspection and showed us via a camera that not only was it cracked in multiple places, but had holes all over it. He gave us a few options for repairing it; his knowledge as well as genuine concern was beneficial and refreshing. Luckily we also scheduled an estimator, Micah, to come too and we were able to get costs between repairing and replacing (with several options). We decided to replace with a much higher efficiency furnace and one sized properly to our home. Hands down, not only did they both provide us great service and knowledge, but without sounding dramatic, they may have saved our lives. This was our first time calling Apollo, but it won’t be our last."
- Sarah B.
"Apollo is an excellent company. I always receive great service. Alex A. was professional and friendly. He kept me informed during the process of checking my furnace and heat pump to make sure they were working properly. The company makes sure you are notified who is coming and when they are on the way. All my interactions with the company have been wonderful."
- Beverly S.