My furnace stopped heating in Niagara this winter. What should I check first?
Swipe for the 1 minute answer
- 01Smell gas? Don't flip switches or use your phone
- 02Get out, then call Enbridge Gas or 911
- 03CO alarm? Everyone out, then call 911
- 01Thermostat on heat, with working batteries
- 02Furnace switch and breaker
- 03Door panel seated properly
- 04Filter not clogged
- 05Outdoor vent pipes clear of snow
AC all summer, then nobody switched it back in the fall. Set it to heat and the house warms up.
The gas was on and the furnace was fine. A bottom panel wasn't seated, so the safety switch stayed open. Once it was back, warm air came right on.
The drain tube clogged or froze, or the pump failed. Take a photo, dry it up, and call an HVAC tech.
One furnace Yifei looks after is about 19 years old. At that age, compare a repair quote with a replacement quote.
- 01New filter before your first November heat
- 02Gently clear snow off vents and gas meter
- 03Away for the holidays? Turn heat down, not off
Tell Yifei how old the furnace is, whether the house is rented, and if you plan to sell. He will tell you straight what to do.
Ask YifeiIf your furnace stops blowing warm air in a Niagara winter, check five things yourself first: the thermostat, the power switch and breaker, the furnace door panel, the filter and the outdoor vent pipes. I've run into this a few times, and it usually turned out to be one of these small things, not a dead furnace. If it still won't heat, or you smell gas or your CO alarm goes off, stop and call a licensed HVAC technician or the gas utility.
Rule out danger first
- Smell gas (rotten eggs): don't flip switches, light anything or use your phone inside. Get out, then call Enbridge Gas's emergency line or 911 from a safe place.
- CO alarm going off: get everyone outside, then call 911.
- Neither of these is a DIY troubleshooting job.
Five things you can check
Two times Yifei saw this
Recently, as the weather turned, Yifei did a walk-through at a client's house. Everything was fine except the thermostat was still set to cool. He switched it to heat and the house warmed up. Running the AC all summer and forgetting to switch back is the most common one.
Another time, a house had no warm air at all. The gas was on and the furnace was fine. Yifei suspected the last home inspector hadn't put the panel back properly, so he got down on the floor to look. Sure enough, a panel at the bottom wasn't seated, the safety switch wasn't pressed, and the furnace wouldn't fire. Once the panel was back in place, warm air came right on.
So if the house was just inspected, the furnace was just serviced or someone just changed the filter, check the panel first.
Water beside the furnace
A client once told Yifei there was water pooling next to the furnace. High-efficiency furnaces produce condensate that drains through a small tube. If the tube clogs or freezes, or the condensate pump fails, water backs up, and some furnaces shut off. Take a photo, dry it up, and have an HVAC tech check the drain before it soaks the floor.
When to replace instead of repair
One house Yifei looks after has a furnace about 19 years old. At that age, get a replacement quote alongside the repair quote and compare. Yifei doesn't replace furnaces himself; that goes to licensed HVAC contractors. TSSA recommends having fuel-burning appliances inspected every year by a TSSA-registered contractor.
Before the cold sets in
- Replace the filter before you turn the heat on in November.
- After big snowfalls, gently clear snow and ice off the outdoor vents and gas meter. Don't chip at them with a shovel.
- Travelling over Christmas or New Year's? Leave the heat on a few degrees lower and have someone check in every few days.
Frequently asked questions
Does a new filter fix a furnace that isn't heating?
A clogged filter can choke airflow and make some furnaces shut down. It's the cheapest thing to try first.
What does the blinking light inside my furnace mean?
Many furnaces have a status light that blinks an error code, usually explained on a label inside the door. Send a photo to your HVAC tech.
Can I fix my own furnace?
Thermostat, switch, panel and filter, yes. Repairs to the gas side need a licensed gas technician.
Want advice for your own house?
The furnace's age, whether the house is rented, and whether you plan to sell all change the right move. Tell me about your situation and I'll tell you straight what to do. Yifei (RE/MAX), efay.ai
Sources
- TSSA: https://www.tssa.org/its-not-just-your-furnace-be-know-when-it-comes-co
- Enbridge Gas: https://www.enbridgegas.com/safety
- Ontario, carbon monoxide safety: https://www.ontario.ca/page/carbon-monoxide-safety