5 Common Reasons Your Furnace Isn’t Working
Is your furnace refusing to start after a period of disuse? Is it running but not blowing warm air? Here are tips for solving five common furnace problems, with advice on when to seek professional furnace repair.
1. My furnace is not turning on at all
Almost all heating problems begin with the thermostat. Double-check that your thermostat is on and the batteries aren’t low. Also, switch your fan from “Auto” to “On” to confirm it’s working.
If the thermostat is functional but the furnace still is not on, check your furnace’s power source. For oil furnaces, make sure there’s oil in the tank. For gas, make sure the supply valve is open. For electric furnaces, turn off the power and check your circuit breaker. Especially if you’ve recently lost power or have other appliances on the same circuit, the breaker might have blown. You can reset it by switching it off and then back on again.
If checking the thermostat and power source doesn’t produce results, check your furnace itself. Does the blower motor have a separate reset button? If so, reset it. Has the pilot light gone out? If so, check your owner’s manual for lighting instructions. If you can’t identify a cause, call a professional for further diagnostics.
2. My furnace is not turning on automatically
It’s frustrating to feel the temperature dropping without the furnace kicking on. The first thing to check is your thermostat. With the thermostat set to “Heat,” and with your fan set to “On” or “Auto,” try raising the target temperature by 5 degrees. If this does not trigger a response, check the ambient air around the thermostat. Is it unusually warm? Try adjusting any nearby heat source (e.g., a lamp or space heater). If this doesn’t work, check your furnace for a broken or dirty belt or sensor. If you cannot clean or replace these yourself, call a technician for professional help.
3. My furnace is not blowing hot air
Why do furnaces sometimes blow cool air? Often, the fan has been set to “On” rather than “Auto.” If your fan is always running, it will stop blowing warm air when the target temperature is reached, and instead, it will blow cool air.
First, check the thermostat’s target temperate and raise it by 5 degrees if necessary. Then set the fan to “Auto.” Also, double-check the thermostat batteries and replace any that are getting low. Finally, make sure nothing is blocking your vents, air ducts, or heating registers. Check your air filters to verify they are clean.
A major culprit for airflow blockages is dirty air filters. The best practice is to clean your air filters once a month. For professional cleaning, including the whole unit or the duct system, call a technician.
4. My furnace runs briefly but then stops
If your furnace will not run for more than three minutes at a time, the system may be short cycling. The short may be caused by a malfunctioning thermostat or heat exchanger. Call a professional for diagnosis and repair.
5. My furnace smells weird
If you notice an odour, do the following, depending on the smell:
Oil, rotten eggs, or sulphur
Call a professional furnace technician immediately. Open your windows, don’t light any matches or flip any switches, and evacuate if the smell grows stronger. Leaking oil is dangerous, and it can smell like sulphur because of chemical additives in the natural gas. The one exception to calling for help is if you recently replaced the oil and may have spilled a few drops outside the tank. Even then, if the smell does not fade after a day or two, you should call a professional.
If you have an oil-fired furnace, it’s best to call a technician once a year to change the oil filter, check the oil nozzle, and perform other preventative maintenance. Taking small steps to care for your furnace regularly can prevent major problems later on.
Hot Wires or Electrical Burning
Turn off the power to your furnace immediately. In older furnaces, motors may generate too much heat and melt the insulation around wires, triggering sparks and fires. Call a furnace technician to assess the situation.
Dust, must, or dirty socks
Though unpleasant, a musty smell is the easiest to deal with! In most cases, you merely need to clean or replace your air filter. You can also use a non-acidic cleaner to scrub the evaporator coils in the furnace. If the smell persists, call a technician to check your air ducts for mould or bacteria.
It’s best to clean and replace your air filter regularly – even once a month for forced-air systems. If your household has problems with dust or allergies, you may want to clean your air ducts yearly. Otherwise, a professional cleaning every 2-3 years may be enough to keep the ducts functioning well.
My furnace is working! How do I keep it that way?
Congrats! Act now to make sure your furnace stays in tip-top shape. Furnaces are complicated; they come in many types—oil, gas, electric, hydronic—and need individualized care.
The best place to start is your user manual. Follow its tips for regular cleaning and maintenance. At a minimum, do a yearly checkup and cleaning on your unit and ductwork. A deep cleaning and intensive maintenance may be needed more often.
If you don’t have enough time to maintain your furnace on your own, consider investing in regular maintenance by a qualified technician. Often a small expense upfront will prevent major problems down the road. A little loving care can keep your furnace in peak condition for years to come! You can also contact Smile HVAC for furnace maintenance. We also provide furnace installation and repair services. Contact us using the button below or simply call 437-777-4555