This article was crafted with the help of Pat and Steve Nugent from John Nugent & Sons

After months of inactivity—and perhaps too little attention paid to seasonal maintenance—it’s common for heaters to malfunction when turned on in the winter. 

Brothers Pat and Steve Nugent of Virginia-based John Nugent & Sons point out that a lack of maintenance is the root cause of many heater problems. They add that malfunctions sometimes result from user error or other minor problems that homeowners can resolve themselves. 

Pat and Steve encourage homeowners to learn a little about their HVAC system so they’ll know when to implement a quick fix and when to enlist the help of a contractor.

Before You Call a Professional

When the heater malfunctions, Pat and Steve say there’s a list of things homeowners can check themselves before calling a trained technician. Even if the following strategies don’t work, at least you’ll have covered the basics before enlisting professional help (and you’ll know what the problem isn’t).

Make Sure the Thermostat Has Batteries and Is Set Correctly

Homeowners who have used analog thermostats for decades may be surprised to learn that their new digital thermostat requires batteries. If the thermostat is totally unresponsive, check the owner’s manual for instructions on changing the batteries and other troubleshooting tips before calling a pro.

Pat adds, “A lot of times, people accidentally hit the wrong button on the thermostat—either they hit ‘Cool’ when they meant ‘Heat,’ or they’ve just turned on the fan, not the heater.”

Check the Air Filter

Changing the air filter is the easiest maintenance task to perform and also the easiest to forget, which can lead to several different problems. “Homeowners should always check their filter,” says Steve. “

A dirty filter can be the cause of issues like poor airflow—even to the point where the unit overheats and shuts off.” If your heater turns on but produces tepid air or turns on and off intermittently, the filter may be so dirty that it’s interfering with normal operation. 

Inspect and change the air filter, and then consult a professional to confirm the heater didn’t suffer any lasting harm.

Check the Circuit Breaker and the Emergency Shutoff Switch

If the furnace doesn’t seem to be getting power, the circuit breaker may have been tripped. 

Pat and Steve say that while homeowners can reset the breaker themselves, they should be aware that a repeatedly blown breaker indicates a more severe problem—perhaps the blower motor going bad.

If the motor restarts after the breaker’s been reset, Pat and Steve recommend keeping an eye on the unit until it’s been serviced, making sure not to leave it on while you’re out of the house.

When the heater won’t turn on, it may also mean that the emergency shutoff (a switch near or on the unit that resembles an ordinary light switch) is simply switched off. This common oversight can be easily resolved by flipping the switch to “ON.”

Turn the Power off and On

Advanced thermostats can lock out users if the diagnostic system detects a problem with the main unit. When that happens, Pat recommends shutting off power to the unit and then turning it back on again.“

If it restarts and keeps running, that doesn’t mean you shouldn’t have a qualified technician check it out, but at least it’s working temporarily,” he says. “If it immediately goes back into lock-out mode, contact a technician right away.”

Unfortunately, not every problem can be tackled without the help of a professional. Luckily, Pat and Steve provide additional helpful information for identifying more complex problems and working with your technician to resolve them. 

Check the Best Picks blog tomorrow for more diagnostic tips along with Pat and Steve’s thoughts on HVAC maintenance and safety.

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This spotlight article was crafted with the help of John Nugent & Sons, an Air Conditioning & Heating Best Pick in Virginia. While we strive to provide relevant information to all homeowners, some of the material we publish may not pertain to every area. Please contact your local Best Pick companies for any further area-specific advice.