Is your furnace not turning on, working intermittently, or doing things it normally doesn't do? A failing furnace control board is one possible cause.

At SDG Duct Cleaning, we're HVAC technicians—not just duct cleaners. We provide furnace repair and troubleshooting in Cornwall, Ontario and throughout the SDG area, and furnace control-board problems are one of the issues we can diagnose.

The control board plays an important role in the operation of a modern gas furnace. It helps control the furnace's heating sequence, including the inducer motor, ignition system, gas valve and blower.

When the board fails, your furnace may stop working altogether or develop unusual and sometimes intermittent problems.

Common Signs of a Bad Furnace Control Board

Some symptoms that may lead us to investigate the furnace control board include:

• Furnace won't turn on
• Furnace works sometimes but not others
• Furnace starts and then unexpectedly shuts down
• Inducer motor doesn't start
• Hot surface igniter doesn't energize
• Gas valve isn't receiving power when it should
• Blower motor doesn't start
• Blower motor won't shut off
• Furnace isn't following its normal startup sequence
• No diagnostic light on the furnace board
• Burn marks or visible damage on the control board
• Unusual or inconsistent furnace fault codes

However, these symptoms do not automatically mean you need a new furnace control board.

That's where proper furnace diagnosis becomes important.

Is It Actually the Furnace Control Board?

We've worked on enough furnaces to know that it's easy to blame the control board when something isn't working.

For example, if your furnace inducer motor doesn't start, the problem could be the inducer motor, control board, wiring or another part of the furnace's control circuit.

If the igniter doesn't glow, that doesn't automatically mean the igniter is bad.

If your blower won't shut off, that doesn't automatically mean you have a bad control board either.

The furnace needs to be diagnosed before parts are replaced.

As HVAC technicians, we can follow the furnace's sequence of operation and determine where that sequence is stopping. We can then test the appropriate components to determine what's actually causing the problem.

My Furnace Has Power but Won't Start

This is one of the complaints that can lead to a control-board investigation.

You may hear nothing happening even though the furnace has power and the thermostat is calling for heat.

Or perhaps the furnace starts the heating sequence but stops partway through.

Either situation requires further diagnosis.

Sometimes the repair is relatively simple. Other times, we may find that the furnace control board has actually failed and needs replacement.

The important thing is knowing which one you're dealing with.

Furnace Control Board Diagnosis in Cornwall, Ontario

If your furnace isn't working properly, you don't need to call us and say:

“I need a furnace control board.”

You can simply tell us:

“My furnace won't turn on.”

“My furnace works sometimes and then stops.”

“My blower won't shut off.”

“The furnace isn't lighting.”

“My furnace is flashing an error code.”

That's enough to get started.

SDG Duct Cleaning provides furnace repair in Cornwall and surrounding SDG communities during our regular service hours. We'll troubleshoot the furnace and determine whether the problem is the control board or something else in the heating system.

Contact SDG for Furnace Repair

If you think you may have a bad furnace control board or simply don't know why your furnace isn't working, contact SDG Duct Cleaning to schedule a service call.

We provide furnace troubleshooting and repair throughout Cornwall, Long Sault, Ingleside, Lancaster, Williamstown, Martintown, Apple Hill and surrounding SDG communities.

We're HVAC technicians—not just duct cleaners.