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How to Troubleshoot a Furnace Heating Problem

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woman setting thermostat

As with other systems, your furnace can fail at the most inconvenient time. You can address some of your furnace issues when it ceases to provide enough warmth. Here are the steps you can take to troubleshoot your system.

Check the Shutoff Switch

If your furnace is not heating, the best approach is to start with the most basic concepts. It is possible that someone turned off the shutoff switch or that it was left off after the last service. It is usually located next to the unit and is often on the wall.

If this switch is on, check whether the circuit breaker has tripped. You can flip it on to restore the power to your unit. If the furnace does not start after this attempt, the problem could be elsewhere in your system.

Troubleshoot the Blower Fan Limit Switch

The purpose of the blower fan limit switch is to turn the blower on and off. It is a mechanism that prevents your equipment from overheating in case of a malfunction. Incorrect settings of the limit switch could be the reason your system is not producing warm air.

Different models of furnaces have limit switches with varying settings and configurations. Some furnaces have a manual “ON” option that will make the blower run continuously. Certain furnace models can work with a running blower, but this setting could prevent your system from heating the interior sufficiently.

Changing the fan switch configuration to “AUTO” might restore your equipment’s functioning. However, tampering with the limit switch can be dangerous. If the furnace overheats, it can crack the heat exchanger and allow toxic fumes to escape. If you have any questions or hesitation, turn off the system and call emergency service for the safety of your home.

Ensure the Thermostat Is Working

Sometimes the reason your furnace is not working is because of the thermostat settings. The thermostat settings may be too low, preventing the system from heating your home adequately. Adjust the settings, and test your furnace.

The thermostat may require a battery replacement. After replacing the battery, check to see whether the thermostat is responding. If it is not working, it may be time to consider a replacement.

You can replace your thermostat with a more reliable programmable device. Programmable thermostats can send error messages with details of the fault. That way, it is easier to identify the problem when your system malfunctions.

Another advantage of a programmable thermostat is that it regulates interior temperatures more precisely. You can save energy and extend the life of your equipment. If you’re located in or around Jamesville or the Albany area, you can rely on us at Holbrook Heating & Air Conditioning for thermostat installation or any other heating repair issue.

Address Airflow Blockages

Another reason your furnace is not working or producing enough warmth could be airflow blockages. Airflow obstructions can force the blower to run continuously to avoid internal overheating. You must address airflow problems because they can age your furnace and reduce its lifespan.

One of the most common culprits for an airflow problem is a clogged filter. We recommend changing or replacing this at least once a month, depending on the type of filter.

Other causes behind airflow issues are blockages and leaks in the air ducts. Your home’s ductwork is the component of the system that channels air to different parts of the building. When it is defective, it will affect your equipment’s performance and provoke indoor air quality concerns.

If you notice dust on surfaces in your home, it could be a sign of ductwork leaks. Rumbling and popping sounds are other symptoms of defective air ducts. They indicate that there is a pressure imbalance within the ductwork.

Ductwork cleaning is one of the preventive maintenance tasks recommended by HVAC system technicians. If there are punctures in your ductwork, a professional service can seal the cracks and holes.

Your ductwork can waste between 20% and 40% of the energy from your system. Defective air ducts will end up incurring unnecessary expenses in the long run, so you should call a repair service as soon as you notice a problem.

Troubleshoot the Ignition System

If your furnace fails to turn on, it could be an issue with the ignition system. Older models have a flame that burns continuously. The purpose of the pilot is to light the gas when you switch on your furnace.

When the flame keeps going out, your furnace will not turn on. Several issues could cause the pilot light to fail. The pilot light may have debris that prevents the flame from lighting. When that happens, you may notice a foul odor from your equipment.

If the pilot produces a mostly yellow glow, it is another indication of combustion problems. It should be clear blue with only a tip of yellow. Otherwise, the flame will not be hot enough to signal the system to start heating.

Pilot light problems are common, but they can be hazardous if you don’t exercise caution. Gas can escape from the system into your home. For your home’s safety, consider consulting the professional team at Holbrook Heating & Air Conditioning.

Clear the Drain Line

High-efficiency condensing furnaces have a drain line to channel moisture away from the system. They have a heat recovery system that produces water as a byproduct of combustion. Gases from the primary heat exchanger circulate through tubes as vapor condenses into water droplets.

During the winter season, the drain pan can fill up and overflow since the furnace runs most of the time. Sediments can cause clogging, forming pools of water around your equipment.

If the drain line is clogged, your system may activate a shutoff mechanism to protect internal components. The water from the system is acidic and can damage your equipment, flooring and walls. It can also encourage microbial growth to spread.

You can clear the clog by snaking it as you would your kitchen drain. You may also use a vacuum to remove the debris from the system. Another solution is to force a jet of water from a hose into the drainpipe.

If your furnace fails to start, it could be other components of your system. Consider calling an experienced heating technician to examine your equipment.

When Should You Call a Technician?

You can use the tips shared here to troubleshoot your furnace, but if you are having problems, it is always advisable to consult a professional service for assistance. You can trigger other complications if you fiddle with parts of the system that you don’t understand.

Professional service is also essential for your safety. If you suspect gas leaks, switch off your system and wait for a professional to arrive.

A burning smell could be a sign of the blower overheating. You may also notice a pungent odor when your gas leaks. Both issues could trigger fire hazards in your home and should always be taken seriously.

Holbrook Heating & Air Conditioning is a BBB-accredited company with an A+ rating. As a family-owned business, we provide exceptional customer service to our clients in Jamesville and Upper New York State. Our team is certified by the NCI and recognized by the ACCA (Air Conditioning Contractors of America). We are a Lennox Premier Dealer, but we have experience fixing Rheem, Mitsubishi and virtually all makes and models of furnaces. You can rely on our staff for heating and cooling installation, repair and maintenance as well as indoor air quality and water heater solutions. Call us our team today for timely repairs.

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