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

Bradford White Ultra Low NOx D series gas error code 2 flashes

Flue damper test circuit not working, damper stuck open

Needs attention soon

Also written as two flashes, 02

Quick answer

On Bradford White Ultra Low NOx D series gas, 2 flashes is a fault. It means flue damper test circuit not working, damper stuck open. A first thing to check: Damper not in its proper position or stuck in the open position.

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: Needs attention soon
First safe check: Look through the draft hood outlet and confirm the damper is present and moving when the burner lights.

Checked 2026-09-26

What 2 flashes means on this model

The control powers the flue damper and checks where it ended up. This code means the damper is not where it should be, most often because it is stuck open, which lets combustion gases out around the draft hood instead of up the flue.

Symptoms you will notice

Two flashes, then a three second pause, repeating
A burning smell near the unit or in the room when it heats
Water goes cold soon after the burner lights
Soot or staining around the draft hood outlet
Unit works sometimes and not others, which fits a damper that is binding

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:

Damper not in its proper position or stuck in the open position
Obstructed venting
Failed damper motor or a jammed damper vane
Damper wiring or cord set not fully connected
Damper switch not set to automatic
Debris or a nest in the flue

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.

Look through the draft hood outlet and confirm the damper is present and moving when the burner lights.
Check the damper switch is set to automatic rather than manual.
Follow the damper cord set from the damper down to the gas control and confirm each plug is fully seated.
Look up the flue for a blockage such as a bird nest, a disconnected joint, or a cap that has fallen into the pipe.

Do not do these

×Do not tape, wedge, or remove the damper. It is a required part of the certified venting arrangement, and a damper missing or blocked changes where the combustion gases go.
×Do not force the damper vane by hand and leave it moved. If it binds it needs the mechanism replaced, not persuaded.
×Do not ignore a burning smell with this code present. A damper stuck open puts exhaust into the room.

When to call a technician

Book a technician, do not keep resetting it

This fault will not clear on its own. Every power cycle gives the control one more failed attempt, and repeated attempts are what turn a cheap part replacement into a seized or contaminated system.

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.

Checking the switch position and the cord set connections is reasonable for a homeowner. The damper, the flue, and anything in the vent pipe is a licensed technician job.

What it costs to fix

Parts

Flue damper assembly $90 to $260. Damper cord set $25 to $70.

Labor

One to two hours to replace a damper. Venting rework $200 to $600 if the flue itself is obstructed or wrong.

DIY or technician