7 flashesBradford White · Ultra Low NOx D series gas · Water Heater

Bradford White Ultra Low NOx D series gas error code 7 flashes

Flammable vapour sensor or resettable thermal switch fault

Stop using it

Also written as seven flashes, 07

Quick answer

On Bradford White Ultra Low NOx D series gas, 7 flashes is a fault. It means flammable vapour sensor or resettable thermal switch fault. A first thing to check: Flammable vapour actually present in the air around the unit.

Applies to: Bradford White Ultra Low NOx D series gas; Bradford White Ultra Low NOx residential D series gas codes · Water Heater
Type of code: Fault; Urgency: Stop using it
First safe check: Think about what has recently been used near the unit. Paint, thinner, solvent, adhesive, and gasoline are the usual triggers.

Checked 2026-09-26

What 7 flashes means on this model

The FVIR system has tripped. A flammable vapour sensor and a resettable thermal switch sit in the combustion path, and this code means one of them has locked the burner out because of a vapour present, moisture on the sensor, an extreme temperature, or an open thermal switch.

Symptoms you will notice

Seven flashes, then a three second pause
Unit will not relight without a reset
Fault appears right after a paint job, a solvent job, or a garage refuel
Fault appears when a gas appliance is run in an attached garage
Restoring power to the burner does not clear it

Common causes

The code tells you what the control detected, not which part failed. These are the causes we see most often, roughly in order of likelihood:

Flammable vapour actually present in the air around the unit
Flammable vapour sensor exposed to excessive moisture
Flammable vapour sensor exposed to extreme ambient temperature
Resettable thermal switch open

What you can safely check

These are homeowner-level checks. None of them need you to open a live electrical compartment or work on gas.

Think about what has recently been used near the unit. Paint, thinner, solvent, adhesive, and gasoline are the usual triggers.
Check whether a vehicle was idled or a fuel-burning tool was run in an attached garage below or beside the unit.
Look at the sensor and the thermal switch for visible moisture or condensation.
Confirm the reset procedure for the unit, which on this platform involves interrupting power rather than only cycling the gas control.

Do not do these

×Do not defeat, bypass, or jumper the vapour sensor or the thermal switch. They are the reason this appliance is permitted to be installed where it is.
×Do not reset the unit and keep trying while the vapour source is still present. The lockout is the protection.
×Do not locate or relocate the unit to get around repeated trips, because a unit that trips repeatedly belongs in a different installation.

When to call a technician

Stop using the appliance and call today

This one is a safety limit, not a nuisance. The control is shutting the unit down to prevent damage or a hazard, and it will keep doing that until the underlying cause is fixed. Running it anyway risks the expensive failure it was designed to prevent.

This is a fuel-burning appliance, so treat anything involving a burner, gas valve or flue as technician work. If you smell gas at any point, leave the property and call the gas utility from outside rather than continuing to diagnose.
If the appliance has stopped mid-cycle, is making a noise you have not heard before, or smells burnt, stop reading here and call. Those are symptoms of something the fault code does not describe well enough.

Identifying the vapour source is something a homeowner can do. Testing and replacing the sensor or the switch is a licensed technician job, because it is a safety device.

What it costs to fix

Parts

Flammable vapour sensor $80 to $200. Resettable thermal switch $30 to $90.

Labor

One to two hours to test and replace the sensor or the thermal switch, plus time to find the vapour source.

DIY or technician