Imagine you’re in the dead of a bitter cold Calgary winter and your furnace stops working. What now? Why did this happen? Furnace breakdowns happen and often, at the worst possible time. Understanding why they happen and how to prevent them and at least knowing when to call for help makes a difference.
At Mr. Mike’s Plumbing in Calgary, we handle heating emergencies on the regular. While we’re known for our plumbing services, we also understand how essential a working furnace is to your home’s comfort and safety. In this guide, we’ll explore the most common reasons furnaces stop working and what you can do about it.
The Most Common Reason: Thermostat Issues
Believe it or not, the common reason a furnace stops working isn’t actually a problem with the furnace itself—it’s the thermostat. Your thermostat controls your heating system and if it’s not working, your furnace won’t either.
Here are the most common thermostat problems:
- Dead batteries (yes, it’s often that simple!)
- Incorrect temperature settings or programming
- Faulty wiring or loose connections
- The thermostat is set to “cool” instead of “heat.”
- A thermostat placed in a poor location (near drafts, direct sunlight, or heat sources)
Before you start panicking, check your thermostat! Make sure it’s set to “heat,” and the temperature is set higher than the current room temperature, and the batteries are fresh. Sometimes, the solution is simpler than you think.
Other Reasons Furnaces Fail
While the thermostat is the most common issue, there are other reasons your furnace can fail. Even if you can’t fix the problem on your own, knowing what the issue is when you reach out to an HVAC professional goes a long way. When you call and explain, you can get your furnace working properly sooner. Here are other common issues:
Dirty or Clogged Air Filters
Dirty air filters also cause furnaces to fail. Your furnace’s air filter traps dust, dirt, pet hair and other particles to keep your system running. When it gets clogged, it restricts airflow, causing your furnace to work harder or shut down completely as a safety feature.
Here are signs to change your air filter:
- Reduced airflow from your vents
- Your furnace runs, but doesn’t heat effectively
- Unusual noises coming from the furnace
- Higher than normal energy bills
- Visible dust and debris on the filter
Generally, air filters should be changed every 1-3 months. Frequency depends on whether you have pets, allergies, and how long you run your furnace in the winter. This simple task prevents costly breakdowns.
Ignition or Pilot Light Problems
Modern furnaces use electronic ignition systems, while older models use a pilot light. Either way, ignition problems tend to cause a furnace to fail. Let us break it down for you.
For older furnaces with pilot lights:
- The pilot light may have blown out due to drafts or gas supply issues
- A dirty or damaged thermocouple can prevent the pilot from staying lit
- Gas valve problems can interrupt the fuel supply
For newer furnaces with electronic ignition:
- The ignitor itself may be cracked or worn out
- Electrical issues can prevent the ignition system from working
- Flame sensor problems can cause the furnace to start and then shut down immediately
If your pilot light won’t stay lit or your furnace won’t ignite, it’s time to call a professional. Gas-related issues require expert handling for your safety.
Lack of Regular Maintenance
Many furnace breakdowns are easily preventable with regular maintenance. Your furnace needs annual tune-ups like your car needs oil changes. Without regular maintenance, small issues can turn into big problems.
Here’s what happens without regular maintenance:
- Dust and debris build up in critical components
- Parts wear out faster than they should
- Small problems go undetected
- Your furnace works less efficiently, costing you more money
- Your warranty may become void
Be sure to book an annual inspection before Calgary’s heating season. It’s the best way to catch problems early, improve efficiency, and extend the life of your system. It’s a small investment that pays off in reliability and peace of mind.
Mechanical Wear and Tear
Furnaces consist of many moving parts, and over time, these components start to wear out. Belts can crack, bearings can fail, and motors can burn out. As your furnace ages, you’re more likely to experience mechanical problems.
The most commonly worn components include:
- Blower motor bearings
- Belts and pulleys
- Limit switches
- Capacitors and relays
- Heat exchangers (in older systems)
Is your furnace starting to make unusual noises? Grinding, squealing, banging, or rattling are some of the most common signs of mechanical wear. Don’t ignore them. That’s a fast way for a minor issue to turn into a complete system failure or a safety hazard.
Gas Supply Issues
If you have a gas furnace, a supply disruption is one of the quickest ways to cause your furnace to stop working. While obvious, most homeowners don’t think of it right away.
Potential gas supply problems include:
- The gas valve to your furnace is turned off (accidentally or during maintenance)
- A problem with your home’s main gas line
- Issues with your utility company’s gas service
- A faulty gas valve in the furnace itself
If you smell gas or suspect a leak, leave your home right away and call your gas utility company’s emergency line. Never attempt to fix gas-related issues yourself.
When to Call a Professional
While some furnace issues can be resolved through simple troubleshooting, such as checking the thermostat or changing the filter, many problems require professional expertise. Call a heating technician if:
- Your furnace won’t turn on at all
- You smell gas or notice unusual odours
- The furnace turns on, but produces no heat
- Your furnace cycles on and off repeatedly
- You see visible damage or corrosion
- Carbon monoxide detectors are going off
At Mr. Mike’s Plumbing, we see heating problems in Calgary all winter long. Let us help diagnose your heating issues.
Keep Your Furnace Running Smoothly
What is the most common reason a furnace stops working? Usually, it’s the thermostat or a dirty air filter, which are both quick fixes. However, this isn’t always the case. For complex problems, reach out to Mr. Mike’s Plumbing. We can help with ignition problems, maintenance issues, and mechanical wear to get your heating system up and running again.
Dealing with a home heating emergency? Contact us today for a quote!
