Bradford White Ultra Low NOx D series gas code Heartbeat
Thermostat calling for heat, normal operation
Which models this applies to. This page covers the Bradford White Ultra Low NOx residential D series gas codes.
What is specific to the Ultra Low NOx D series gas platform
Atmospheric gas water heater with a flue damper and a Honeywell WV4472 electronic gas control, which reports faults as a counted LED flash with a three second pause between repeats. The damper codes have no equivalent on units that do not have one, and the codes are not shared with the condensing platforms of other brands.
Your control board does not print the code. It blinks an LED, and you count the flashes against a legend printed on the board or inside the access panel. Count a full cycle before you read it, because the pattern pauses and repeats.
Quick answer
On Bradford White Ultra Low NOx D series gas, Heartbeat is a normal display state, not a fault. The light brightens and dims in a slow heartbeat because the tank has dropped below the setpoint and the control is asking the burner to fire. Seeing this means the appliance is working as designed. A first thing to check: Normal operation. Hot water has been drawn, or a dishwasher or laundry cycle has started..
- 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
- Status or setup value
- Urgency: nothing to fix
- First safe check
- Run a hot tap for a minute and watch the LED go into a heartbeat. That confirms the control, the gas valve and the burner are all responding to demand.
What Heartbeat means on this model
The light brightens and dims in a slow heartbeat because the tank has dropped below the setpoint and the control is asking the burner to fire. Seeing this means the appliance is working as designed.
Symptoms you will notice
- The LED brightens and dims in a slow heartbeat rather than showing a number
- Hot water at the tap, or hot water is about to appear
- The burner compartment is warm and you can hear it firing
- The heartbeat stops shortly after you stop drawing water
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:
- Normal operation. Hot water has been drawn, or a dishwasher or laundry cycle has started.
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.
- Run a hot tap for a minute and watch the LED go into a heartbeat. That confirms the control, the gas valve and the burner are all responding to demand.
- Time how long the burner runs after a call. A run that never ends on a small draw is a different problem from one that stops when you do.
Do not do these
- ×Do not treat a heartbeat as an unlisted code. It is one of the two documented normal indications on this control.
- ×Do not interrupt the burner mid cycle out of concern about the heartbeat, since stopping it is what leaves a cold pilot.
When to call a technician
Worth scheduling, and worth your own checks first
You can usually keep living with this for a short while, but it will not fix itself. Do the safe checks below first, because a tripped switch or a blocked airflow is a five-minute fix that would otherwise cost you a service call.
- 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.
No service is called for.
What it costs to fix
Parts
None. No parts are involved in normal operation.
Labor
None.
DIY or technician
No service is called for.
Typical US part and labor ranges, 2026. They vary by region, model and contractor, so treat them as a planning figure, not a quote.
Scope of this code
- Code table
- Bradford White Ultra Low NOx residential D series gas codes
- How this model reports the code
- Blinking LED, counted against a legend
- Models in scope
- Bradford White Ultra Low NOx D series gas
- How this platform differs
- Atmospheric gas water heater with a flue damper and a Honeywell WV4472 electronic gas control, which reports faults as a counted LED flash with a three second pause between repeats. The damper codes have no equivalent on units that do not have one, and the codes are not shared with the condensing platforms of other brands.
- Checked
- Confirm on your own unit
- Find the model number on the data plate, then check this code in the service manual for that model. Manufacturers revise code tables between model years, and a revised board can renumber a fault.