Troubleshooting Tips for the Most Common Furnace Problems

When the winter winds blow, nothing feels better than turning up the heat. So what do you do if your furnace starts acting strangely? Maybe you hear a loud noise, detect an odd smell, or can’t seem to get your house to warm up.

Whatever furnace problems you’re facing, you can trust a licensed, certified HVAC technician to set things right. But before you schedule professional heater repair, run through these troubleshooting tips to see if you can solve the problem yourself.

The Furnace Won’t Start

Is your house colder than you think it should be? Why hasn’t has the furnace kicked on by now? Work through your heater problems with these tips:

• The thermostat is set too low: The simplest solution is to raise the temperature a few degrees and see if the furnace turns on.
• There’s no power: If adjusting the thermostat proves fruitless, check your breaker box for tripped circuit breakers and reset any you find.
• The power switch is off: Make sure the separate power switch located on or near the furnace is turned on.
• The motor has overloaded: Wait for 30 minutes to let the motor cool down. Then, press the reset button, which should be located near the motor housing. If the furnace still doesn’t start, wait an additional 30 minutes before pressing the reset button again. Repeat this process one more time before calling a professional for help.
• The pilot light is out: Relight the pilot. If it doesn’t stay lit, try cleaning the pilot opening, depressing the pilot light button fully, and making sure the gas valve is open.
• There’s no gas: Check the gas valve to ensure it’s fully open and that the furnace is receiving fuel.

The Furnace Doesn’t Produce Enough Heat

Maybe your heater runs, but the thermostat never reaches its target temperature. Here’s what might be wrong:

• The filter is dirty: Clean or replace the filter according to the manufacturer’s directions.
• The blower is clogged: Clean out the blower assembly to improve airflow.
• The registers are blocked or closed: Perform a sweep of the entire house, making sure all registers are open and unblocked by furniture, drapes, or rugs.
• The blower belt is loose: Tighten or replace the belt. You may need help from a technician to do this.
• The burners are dirty: Contact a professional to clean the burners.
• The system is imbalanced: Count on an HVAC contractor to rebalance the system.

The Burner Won’t Stay Lit

Without a lit burner, your furnace will cycle off shortly after coming on, a heater problem known as short-cycling. Consider what issues might be to blame:

• The thermocouple is loose or faulty: Tighten the thermocouple nut slightly. If there is no change in furnace performance, hire a professional to replace the thermocouple.
• The flame sensor is dirty: Gently clean the sensor or have it replaced.
• The pilot light flame is set too low: Adjust the height so the flame is about two inches high.
• The electric pilot is faulty: Only a professional can solve this furnace problem.
• The pressure switch keeps tripping: This is caused by improper venting. A dirty air filter, blocked air vents, or ductwork obstructions could be to blame. Address these issues to improve airflow and help your furnace function normally.

The Blower Runs Constantly

Your furnace should operate for several minutes and then cycle back off. Here’s what to do if your furnace runs constantly:

• The thermostat is set incorrectly: Check the thermostat to see if the fan is set to “on” or “auto.” The “on” setting means the blower runs constantly, even when the burners aren’t lit. You can change the setting to “auto” if you prefer, so the blower only operates when the furnace is running.
• The limit switch is malfunctioning: Reset the limit switch. If that doesn’t work, hire a professional to adjust the limit control or replace the limit switch.

The Furnace Operates Loudly

Listen for rattling, squeaking, booming, or banging sounds from your furnace. If you hear anything strange, try these troubleshooting tips:

• An access panel is loose: Check that all access panels are mounted and fastened correctly.
• The drive belts are sticking, damaged, or worn out: Spray squeaking drive belts with a belt dressing. Worn or damaged belts need to be replaced.
• The blower belts are too loose or too tight: Adjust the belts to the correct tension.
• The motor and/or blower needs lubrication: Lubricate the oil ports to help these parts move smoothly and make less noise.
• The burner is dirty: Contact a professional to clean the burner.

Water Leaks from the Furnace

High-efficiency condensing furnaces generate condensation, which could be the source of the water pooling around your furnace. Here’s how to address the leak:

• The condensate hose is kinked or blocked: Check the PVC fitting for debris and blow through it to clear the blockage.
• The condensate pan is leaking: The pan under the furnace could be overflowing, so check if it’s draining properly. Contact a professional if you can’t pinpoint the source of the leak.

Schedule Furnace Repair or Maintenance

The best way to avert furnace problems is to schedule preventative furnace maintenance. Yearly inspections help your technician find and correct system flaws before they escalate into full-fledged breakdowns. In this way, preventative maintenance can save you money and hassle on future repair costs. Of course, if your furnace has already broken down, you need to schedule heater repair before your home becomes even more uncomfortable.

No matter what furnace services you’re looking for, Triple T Heating, Cooling & Plumbing can help. We have been keeping Utah homeowners warm and comfortable since 1974. Contact us today to schedule the heater maintenance or repair services you need. You can reach us at 801-798-7711 if you live in Utah County or 435-275-4011 if you’re a Washington County resident.