Furnaces are essential home features that play an important role in maintaining the appropriate temperature across the indoor space. These heating systems are generally designed to be reliable and efficient over the long term, but every now and then you may notice that it isn’t working as well as it should be—and getting it back to working condition can be crucial so that’s why we compiled a list of simple furnace troubleshooting tips.
The best thing to do would be to call in your trusted local HVAC experts, but there’s nothing wrong with observing the furnace’s behavior, understanding what could possibly be causing the problem, and performing some simple tweaks that can tide you over until the HVAC experts arrive.
Here are some simple furnace troubleshooting tips that homeowners can try:
If the
gas furnace isn’t producing any heat, the cause could be:
- A broken or improperly set thermostat
- A tripped fuse or circuit breaker
- Ignition issues (pilot lights for non-electronic ignition, and hot surface or intermittent pilot for electronic ignition)
You can:
- Set the thermostat to heat mode and to the right temperature setting
- Try changing the dial setting a few degrees up or down
- Replace a blown fuse or reset a tripped circuit breaker
If the gas furnace is producing heat, but not enough, the cause could be:
- Dirty gas burners or air filters
- A clog that obstructs the flow of air to the combustion air chamber
You can:
- Replace the dirty air filter
- Call HVAC professionals to adjust the burners (going DIY is not advisable on this)
If the gas furnace keeps turning on or off, the cause could be:
- Problems with the blower or thermostat
- The air filter is dirty
You can:
- Replace the dirty air filter, or frayed belts
- Adjust the thermostat’s heat anticipator
- Check if the belt has proper tension
If the gas furnace makes a loud noise while it’s on, the cause could be:
- Dirty gas burners (the sound may be a low rumbling, while the burners are on)
- Incorrectly set pilot light (the sound may be a low rumbling while the burners are off)
- A blower belt is slipping, or shaft bearings require oil (the sound may be a high-pitched squeal)
You can:
- Adjust the pilot light
- Tighten the belt, or replace it if it’s frayed
- Apply oil to blower motor lubrication ports
If the gas furnace blower refuses to turn off, the cause could be:
- A broken fan limit control switch
- The thermostat has been set to “fan continuous”
You can:
- Reset the fan limit control switch
- Adjust the thermostat fan’s setting
