Few problems cause homeowners headaches like a bad furnace. Broken furnaces can’t heat your home, leaving you and your family especially vulnerable during those cold winter months. Even worse, it can be tough to know why your furnace is having problems to begin with. 

Some homeowners realize that furnace circuit boards can cause furnaces to fail but don’t know why furnace circuit boards themselves fail. Our team at Leith Heating & Cooling is here to answer the question, “What causes a furnace circuit board to fail?”

You can count on Elgin’s trusted furnace repair service to explain the most common reasons why furnace circuit boards fail. Call us at (847) 565-1568 to schedule a service!

Furnace circuit boards regulate your furnace’s functioning. More specifically, the furnace circuit board provides electricity to your furnace’s parts, such as gas valves, blower motor, heating element, and ignition. Without a circuit board, your furnace wouldn’t be able to turn on or off or heat your home at all.

Below are the most common reasons for a furnace circuit board to fail.

Thermal Expansion

Thermal expansion refers to how constant, frequent temperature changes can cause materials to expand and contract. In particular, furnaces generate an extreme amount of heat, making their inner and outer materials expand and contract. Over time, these thermal shifts can damage your furnace. 

In particular, your furnace’s solder joints and wires can suffer thermal damage after repeat heat exposure. Under these circumstances, your circuit board can disconnect from your furnace entirely, causing power troubles. If you suspect that your circuit board is experiencing thermal damage, don’t hesitate to contact your local professionals.

Broken Blower Motor

Blower motors enable the transfer of hot air from your furnace throughout your home. Without a working blower motor, your furnace will overheat, causing your circuit board to melt. A molten circuit board will, in turn, shut your furnace down.

Wiring, fuses, switches, and transistors, in particular, suffer when a furnace overheats. In addition, a bad blower motor can cause back-drafting, leading to fires. That’s why it’s critical to contact your local furnace experts if you think you have a broken blower motor.

Loose Wiring

Furnaces typically vibrate while generating heat. While this isn’t necessarily something to worry about, it’s cause for concern due to how it affects your unit’s wiring. Constant vibrations and rattling can cause furnace wiring to come undone.

Loose wiring is no joke; it can make your furnace trip your home’s circuit breaker. That’s why it’s crucial to check your furnace for loose wiring when performing regular furnace maintenance. You can tell if you’re having wiring issues if your unit’s indicator light is on.

Bad Solder Connections

If you’re wondering, “What causes a furnace circuit board to fail?” there’s a good chance your unit has faulty solder connections. These connections use Molex plugs to connect your furnace circuit board’s pieces to the wiring. Usually, these plugs come in pairs, with one low-voltage plug and another high-voltage plug.

Expert technicians frequently encounter bad solder connections, no matter the type of furnace. That’s why it’s best to seek professional help if your unit’s Molex plugs aren’t working. They can use a voltage meter and other tools to evaluate your furnace’s electrical capacity.

Dirty Air Filter

Like air conditioners, furnaces rely on air filters to prevent dirt and particulates from entering your system. Unfortunately, filters clog over time, causing your furnace to experience airflow issues. In particular, dirty air filters put extra strain on your furnace, causing overheating that may damage wires and switches on your furnace circuit board.

Broken Transistors

Furnace circuit boards rely on transistors to handle electricity flow. Often, circuit board transistors fail due to power surges, overheating, or plain wear-and-tear. These components are especially vulnerable to thermal expansion issues.

Faulty Relay Switches

Relay switches allow you to turn your circuit board’s components on and off. While these nifty pieces give you the ability to control your furnace’s electricity, they’re especially prone to getting stuck. Worst of all, stuck relay switches typically won’t budge, leaving you unable to control your furnace’s power supply.

Your local furnace experts can try and dislodge your unit’s relay switches. If needed, they’ll install replacement switches or an entirely new circuit board.

Power Surge Damage

Power surges flood your home’s electricity system with extreme amounts of electricity, causing appliances and circuit breakers to shut down. Modern electrical utilities feature built-in surge protectors that guard against power surge damage.

However, power surges can seriously damage furnace circuit boards, burning out fuses, transistors, and wires alike. Sometimes mini-surges that aren’t even powerful enough to turn your home’s electricity off cause circuit board issues. 

Old Age

Furnaces undergo constant stress daily. To make matters worse, they deal with many of the problems listed above. Whether due to thermal expansion or power surges, your circuit board must work hard to function properly.

Furnaces more than ten years old tend to malfunction more than newer units. Under these circumstances, it’s usually best to replace your entire furnace. However, if you own a newer furnace, it’s possible to replace your circuit board without installing a whole new system.

Electrostatic Discharge

Static electricity occurs when someone repeatedly touches carpeted floors, usually by walking on them. As you walk across carpet, your body accumulates a slight but noticeable amount of static electricity. As soon as you come into contact with metal or another conductive material, that electricity transfers from your body to it, resulting in a nasty shock.

This electrostatic discharge (ESD) can cause serious damage to furnace circuit boards, even if you take care to ground yourself before working on your furnace. In particular, ESD wreaks havoc on your control board’s insulation layers, damaging transistors, switches, solder joints, relays, and wiring.

Quality Furnace Maintenance in Elgin, IL

Still not sure what causes a furnace circuit board to fail? Our team has you covered. We proudly help Elgin homeowners with regular maintenance and repair services. 

When you get your furnace maintained, you can count on us to make it work as good as new. Call our Lieth Heating & Cooling experts at (847) 565-1568 to get a quote.

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