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Douglas Cooling & Heating Blog

HVAC Troubleshooting: Gas Furnaces in Birmingham

Gas furnaces are a godsend to stay comfortable in your Alabama home all winter. They have lots of parts, however. If a problem ever arises it could stem from anywhere in your system.

Lucky for you, if you ever experience any of the issues common to gas furnaces, your heater may have a simple fix.

Gas Furnaces Problem: Furnace Won’t Start

This issue has many likely culprits. The most simple is your furnace might not be turned on or your thermostat not set to “heat.” It’s okay! It happens more than you think! Other issues include a faulty thermostat or circuit board.

Solution: Check the wiring connections. If you have a battery-powered thermostat, check if it needs fresh batteries. If neither fixes your problem, you may have a bad thermometer. You can check using an electrical multimeter to see if a circuit is complete.

Your next step is to call an HVAC technician. He or she can check if your furnace has a bad main circuit board, and if so, replace it.

Gas Furnaces Problem: Blower Won’t Shut Off

It’s likely the fan switch on the thermostat is set to “on.” Relays in the control board are stuck in the closed position, so the blower has a constant supply of electricity. Or you have worn contacts in your thermostat. These contacts which control power to the furnace may be at fault.

Solution: An easy thing you can try is first to turn the fan switch on thermostat to “auto.” Next, have an HVAC technician replace the thermostat or control board.

Gas Furnaces Problem: Furnace Keeps Shuts Off Early

If your furnace burner lights but the furnace shuts off soon after, it may be a dirty furnace filter. It might also be a broken flame sensor or a failing thermostat. Call an HVAC technician to diagnose.

Solution: Clean or replace your furnace filter. If your furnace continues to shut off, you may need to replace your flame sensor or thermostat.

Gas Furnaces Problem: Furnace Runs but House is Cold

If you have the proper-size furnace for the size of your home, it should keep your home warm no matter how cold it gets. If it runs constantly but fails to keep your house warm, it’s likely due to your filter or air ducts.

Solution: You may have a dirty filter. It may be the wrong type of filter for your furnace. This sometimes restricts airflow throughout your home. Your filter could be installed backward. All of these issues have pretty simple fixes. Your furnace’s manual should list the proper size for your unit.

If none of those suggestions remedy your cold air issue, you may have a leak somewhere in your air ducts, in which case you’ll need to have it sealed per Energy Star recommendations.

Gas Furnaces Problem: Furnace Makes Loud Noises

Any extra noise gas furnaces make are most often the result of old age or a broken part somewhere in the unit. It may also be a lack of maintenance.

Or, if you have a single-stage gas furnace which continuously runs on high capacity, it may just be the nature of your unit. These types of gas furnaces tend to be loud.

Solution:  Clean or replace your furnace filter — dirty ones can cause whistling. Otherwise, no matter what noise your furnace makes, your next best bet is to call an HVAC technician to help you diagnose and fix the issue.

It’s likely a part needs to be fixed somewhere. You may need a blower motor replacement. It’s possible your furnace cabinet leaks or ductwork near the furnace is loose.

We Can Help You Solve Your Problems with Gas Furnaces

Don’t sweat it if after trying any of these troubleshooting ideas your gas furnace still doesn’t work — the friendly expert HVAC technicians at Douglas Cooling & Heating have seen just about everything.

They can help you get your heat back up and running in no time. Call us to schedule a service call if you experience any issues common to gas furnaces.

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