Can I reset my Lochinvar boiler to clear the Flue Sensor Fault code?

You can reset once if your manual says it's safe. If the code returns, stop resetting — repeated resets on a genuine fault, especially gas or overheat faults, can be unsafe and may worsen the problem. Book a licensed repair instead.

Is the Flue Sensor Fault fault dangerous?

Treat it as urgent. This code involves systems where continued operation can be unsafe. Turn the boiler off if it keeps recurring and call for a licensed repair; if you smell gas, leave and call your gas utility's emergency line.

How much does it cost to fix a Lochinvar Flue Sensor Fault fault?

Cost depends on the underlying cause — some causes (like low pressure or a dirty sensor) are minor, while others (like a gas valve or control board) cost more. We diagnose first and give you a clear price before any repair.

Lochinvar Error Code

Lochinvar Error Code Flue Sensor Fault

Flue temperature sensor fault or flue over-temperature.

Call 778-909-5731 Get a Free Quote

Licensed & Insured Gas-Certified Technicians Serving Vancouver Since 1999

If your Lochinvar combi boiler is showing error code Flue Sensor Fault, here's what it means: Flue temperature sensor fault or flue over-temperature. This is an urgent fault. Stop using the boiler if it keeps recurring and book a licensed repair promptly — especially if it involves gas, ignition, overheating or the flue.

Lochinvar boilers report faults using descriptive smart system faults. Knowing the code helps a technician arrive prepared with the right parts, which usually means a faster, lower-cost repair.

What causes the Flue Sensor Fault code?

Error Flue Sensor Fault on a Lochinvar boiler is most commonly caused by one of the following:

Heat exchanger fouling
Sensor fault

What you can safely check first

Note the exact code and your boiler's model number
Check the pressure gauge — low pressure triggers many faults
Confirm the gas supply is on and other gas appliances work
Reset the boiler once, per the manual, only if it's safe to do so
If the code returns, stop and call a licensed technician

Why this needs a licensed technician

Resolving a Flue Sensor Fault fault almost always involves the gas, combustion, sensor or pressurized side of the appliance. Under BC's Safety Standards Act, that work must be performed by a licensed gas fitter — and doing it correctly protects your warranty and your safety. We diagnose Lochinvar boilers, carry common parts, and verify clean combustion before returning your boiler to service.

Smell gas or suspect carbon monoxide? Leave now.

If you smell gas, hear hissing, or your CO alarm sounds, leave the building immediately and call your gas utility's emergency line from outside. Do not operate switches or relight the appliance. Once you are safe, call us for a licensed repair.

Call 778-909-5731

Frequently Asked Questions

Other Lochinvar codes & help

Lochinvar Ignition FailureBoiler failed to establish a flame within the trial period.Lochinvar Flame LossFlame lost during a heating cycle.Lochinvar High LimitWater temperature exceeded the high-limit setting.Lochinvar Supply Sensor FaultOutlet temperature sensor out of range.Lochinvar Return Sensor FaultReturn temperature sensor out of range.All Lochinvar Error CodesFull list

Fix Your Lochinvar Flue Sensor Fault Fault

Free, no-obligation quotes across Greater Vancouver. CombiBoiler.ca — A division of ROMA Heating Ltd..

Call 778-909-5731 Email Us