Why Your Furnace Gets Red Tagged in Ontario and What You Should Do Next

Every winter in York Region, homeowners get hit with the same surprise. A furnace gets red tagged. The gas is shut off. The house goes cold.

Most people panic. You need a clear plan.

What a Red Tag Means

A red tag means your gas appliance is unsafe to operate. Enbridge or a licensed gas technician found a code violation under CSA B149. The issue must be corrected before the gas is restored.

Common reasons furnaces get red tagged in Ontario:

• Cracked heat exchanger

• Carbon monoxide detected in supply air

• Improper venting or disconnected 636 vent pipe

• Gas leaks on black iron or fittings

• Missing burner door

• Unsupported gas line not spaced per code

• Rubber plumbing couplings used on exhaust

Carbon monoxide in supply air is serious. Even 1 to 2 PPM in the ductwork indicates combustion gases are leaking where they should not.

What Happens After the Gas Is Shut Off

When a furnace is red tagged:

• The gas valve is turned off

• The gas line may be capped

• The customer receives a copy of the violation

• Repairs must be completed by a licensed gas technician

You cannot ignore it. The system stays off until the violation is cleared.

How a Professional Fixes the Problem

The solution depends on the issue.

If the heat exchanger is cracked:

• The furnace must be replaced

If venting is installed incorrectly:

• Remove improper fittings

• Install approved 636 venting

• Seal and support per manufacturer specs

If a gas leak is suspected:

• Isolate the appliance

• Pressure test the line

• Hold 15 PSI for required duration

• Confirm no drop on manometer

• Document results

If piping is unsupported:

• Install proper strut or approved hangers

• Follow spacing table in B149

Every correction must meet code. No shortcuts.

Why Proper Documentation Matters

When clearing a red tag, documentation protects you and the homeowner.

A proper resolution includes:

• Written repair description

• Photos before and after

• Pressure test results if applicable

• Confirmation the violation was corrected

In many cases, the resolution must be submitted through the Enbridge contractor portal.

If the repair is not documented correctly, the violation may remain open.

How to Avoid a Red Tag in the First Place

Most red tags are preventable.

Book annual furnace maintenance. During a proper inspection, a technician should:

• Perform combustion analysis with printout

• Test for CO in supply air

• Inspect venting connections

• Check flame sensor and burners

• Inspect heat exchanger

• Verify gas pressure

Skipping yearly service increases risk of failure and shutdown during peak winter.

If Your Furnace Is Red Tagged in Newmarket or York Region

Do not wait.

A cold house in February becomes an emergency fast. Get a licensed G1 gas technician to assess it immediately.

If the furnace is not repairable, request a written estimate for replacement. Ask about venting upgrades. Confirm warranty details. Make sure the gas line is properly capped until installation.

Safety first. Heat second. Paperwork done right.

If you need help with a red tagged furnace in Newmarket, Aurora, Vaughan or Richmond Hill, book a proper inspection and get it handled the right way the first time.