Keep this maintenance checklist handy to keep your gas furnace roaring for years to come
Don't wait for outside temperatures to take a dip to check in on your furnace and ensure that everything's working properly. Regular furnace maintenance, along with an annual check-up from a qualified furnace pro, will help you avoid breakdowns that can leave you chilly on a frigid day. Here’s a complete gas furnace maintenance checklist to follow.
Follow this DIY Furnace Maintenance Checklist
First, let’s cover some basic gas furnace maintenance tasks you can do to keep it running in top shape.
1. Change the Filters
You should change furnace filters on this schedule:
No pets: every 90 days
With pets: every 60 days
If someone in your home has allergies: every 30 to 45 days
Not changing your filters regularly allows dirt, debris, and particles to build up and slow airflow—which means less efficiency.
2. Clean the Burners
Your burners should be removed and cleaned every so often. Burners are susceptible to soot and condensation that can prematurely age your furnace. While a pro will do this as part of an annual check-up, you can and should check them yourself as often as you change the filters.
After turning off the furnace and shutting the gas valve, remove the burners and vacuum or wipe them down with a cloth. The flame sensor, which detects whether the pilot light is on, should also be cleaned at the same time. Take it out and remove any dirt with a cloth.
3. Check the Gas Line
Check for signs of leaking—like a hissing sound or a tell-tale smell of propane—starting from the shut-off valve. If you hear a hiss or smell propane, shut off your main valve and call a pro right away.
4. Test the Smoke Detector and Carbon Monoxide Detector
While your home's smoke detector and carbon monoxide detector aren't part of your gas furnace, your furnace inspection is a great time to remember to test and replace the batteries in them. You should also test your carbon monoxide detector. Make sure your detectors are at least 15 feet away from your furnace to avoid false alarms from the small amount of carbon monoxide (CO) given off when your furnace is starting up.
What to Expect During an Annual Furnace Inspection
An annual furnace maintenance check-up will cover all of the easy DIY tasks above, as well as some more complicated steps best left to the pros. Here’s what to expect during your annual inspection:
1. Clean and Oil Motors and Bearings
A furnace pro will clean and lubricate internal furnace components to prolong their life and prevent failure.
2. Check Thermostat
The thermostat should be checked for functionality and accuracy. You can also ask the furnace pro doing the inspection to recalibrate your thermometer to help reduce energy costs.
3. Ignition and Flame
Your furnace pro will cycle the furnace on and off to check ignition and flame performance. They may replace your ignitor or adjust the pilot valve if necessary.
4. Flush Drains and Traps
The HVAC specialist will flush the furnace’s drains and traps and check for leaking water during the inspection. Most furnaces have at least two internal drains that connect to the unit's trap. These drains help to clear the heat exchanger and vent. It's essential to drain condensation to prevent accumulation that could stop proper combustion. Water leaks are signs of issues like loose connections, cracks, or holes within the condensate drain line. Flushing the drain and traps can also identify if there is a drain line clog.
5. Check Venting
Confirming that vents are clear is important because the furnace vents direct gas away from your home through the flue pipe. The furnace pro will verify that there is proper, unobstructed ventilation by looking for debris, leaks, and sloping. Common signs of clogged venting include rust and water streaks on your furnace's vent or flue.
6. Inspect and Clean Blower
The unit's blower should be removed and cleaned. The performance of the blower's run capacitor should also be checked.
7. Adjust and Tighten Panels
Your furnace pro will ensure that all unit panels are tightly in place because jostled panels can reduce efficiency, make rattling noises when running, and potentially cause a system shutdown. A front panel that doesn't close properly could also put your home at risk for unhealthy carbon monoxide (CO) exposure.
8. Check Controls and Safeties
Controls and safeties should be tested to verify that they won't interfere with the performance of other components. Controls and safeties have built-in triggers that preempt dangerous malfunctions and overloads. Your furnace's main safety feature is the limit switch that shuts off the gas supply if heat or flames are detected beyond the unit's burner chamber. Your furnace may also feature controls that display error messages. Furnaces typically will not restart once a control or safety is triggered and must be manually reset.
9. Check Flue Pipe
The flue pipe is responsible for removing fuel by-products from your home. A pro will check your flue pipe for proper fit and flow.
10. Check Heat Exchanger
Heat exchangers only require visual inspections. Some tell-tale signs that an exchanger is having an issue include a formaldehyde-like smell, soot, cracks, and noises.
11. Check Manifold Pressure
Your pro will check and adjust the gas pressure delivered from the gas valve to the burners.
12. Air Openings
You'll find your furnace's air intake vent located on the side of your house; and its return ducts are typically placed in rooms, hallways, and stairwells. Vent blocks can cause anything from carbon monoxide buildup to pressure imbalances that make your unit inefficient. As part of the maintenance appointment, the pro will inspect all openings for blockages or restrictions. Dust, mold, pollen, pet dander, leaves, hair, soil, and critters can all get into your air openings to create blockages.
13. Extras
Most furnace inspections rely on visual and performance-based inspections of key components. You can often upgrade your inspection to include:
Static air pressure test
Temperature-rise assessment
Gas-pressure testing
Combustion-gas analysis
These test points can serve as important performance measures if you have an older unit.
The Bonus Step: A General Cleaning
The furnace area is usually left in pristine condition following an inspection. Dust is common on furnaces because they’re usually found in basements and utility closets, so you can also routinely wipe down the furnace’s surface and vacuum around it to keep the area clean.
Make a Plan to Get Your Furnace Checked
If you're just learning that gas furnaces need to be inspected every year, get in contact with a top-rated HVAC contractor today to book an appointment. Most pros will put you on a service plan that includes your annual inspection with some free service calls thrown in the mix.
While a furnace pro is important for your annual inspection, you shouldn't stay a stranger to your furnace the rest of the year. Regular furnace check-ups protect your furnace warranty; some warranties become void if you don't properly maintain your unit.
Regular furnace check-ups also save you money by boosting your system's energy efficiency—which means no heating costs flying out the window at your house. You can even catch a pricey problem before it happens.
Pop into the furnace room regularly to look for signs of leaks, corrosion, or strange odors. Put filter changes on your calendar for every 30 to 90 days, and schedule a furnace check-up once a year. Taking care to keep the furnace area clean and properly ventilated will boost it’s efficiency and dependability through many more cold months.
