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Error code reference

Bradford White Water Heater Error Code 1 short flash once per second

Weak pilot signal detected on last call for heat.

Bradford White codesBradford White water heater codes

Weak pilot signal detected on last call for heat.

First step from the service manual

See burner inspection on page 13; check pilot tube for blockage/restriction; check pilot electrode for oxidation; check wire damage to pilot assembly or connection at gas valve.

The complete diagnostic procedure includes additional test steps, resistance specifications, wiring diagram references, and component test points.

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What 1 short flash once per second means on a Bradford White water heater

The 1 short flash once per second diagnostic code on a Bradford White water heater indicates that a weak pilot signal was detected during the most recent call for heat. This code is generated by the gas valve control module, which continuously monitors the microamp output of the thermocouple or thermopile sensor in the pilot assembly. When the sensed signal falls below the minimum threshold required to confirm a stable pilot flame, the control locks the condition and stores it as a fault. The flash pattern repeats at a steady one-per-second rate to distinguish it from other fault codes in the sequence.

The pilot signal chain includes the pilot tube, the pilot orifice, the electrode or thermocouple tip, and the wiring harness that connects the pilot assembly to the gas valve. A weak signal can result from a partially blocked pilot orifice delivering insufficient gas to sustain a robust flame, oxidation or carbon fouling on the thermocouple or electrode tip reducing its ability to generate proper millivolt output, or damaged and corroded wiring creating resistance in the signal path back to the gas valve.

Burner inspection as described on page 13 of the technical documentation is the recommended starting point. This involves visually inspecting the pilot tube for debris, spider webs, or scale restricting gas flow, examining the electrode tip for oxidation or buildup, and checking all wire connections at the pilot assembly and gas valve terminal block for corrosion, looseness, or physical damage to the insulation. Addressing any of these conditions typically resolves the weak signal fault.

Source: manufacturer service documentation.

Common causes of 1 short flash once per second

  1. 01

    Blocked or restricted pilot tube

    Wiring / connection

    Debris, spider webs, or mineral deposits inside the pilot tube can reduce gas flow to the pilot, producing a weak flame that generates a low sensor signal. Inspect the pilot orifice and tube for any visible obstruction and clear with compressed air or appropriate cleaning tools.

  2. 02

    Oxidation or fouling on pilot electrode or thermocouple tip

    Part replacement

    Carbon buildup or oxidation on the thermocouple or electrode tip reduces its ability to generate adequate millivolt output even when the flame is present. Light cleaning of the tip surface may restore output, but a heavily corroded component typically requires replacement.

  3. 03

    Damaged or corroded wiring to pilot assembly

    Part replacement

    Worn insulation, pinched conductors, or corroded terminals in the wiring harness between the pilot assembly and the gas valve introduce resistance that weakens the signal reaching the control. Inspect the full length of the harness and all connection points at the gas valve terminal.

  4. 04

    Loose connection at the gas valve

    Wiring / connection

    A connector that is not fully seated at the gas valve terminal block can cause intermittent or consistently low signal readings. Check that all pilot assembly leads are firmly connected and free of corrosion at the gas valve junction.

  5. 05

    Failing thermocouple or thermopile

    Part replacement

    A thermocouple or thermopile that is aging or beginning to fail may produce a signal that is within range during some cycles but drops below the required threshold during others. If cleaning and connection checks do not resolve the fault, replacing the sensor is the next step.

See the test procedure for each cause

Frequently asked questions about 1 short flash once per second

What does 1 short flash once per second mean on a Bradford White water heater?
This flash pattern indicates that a weak pilot signal was detected during the last call for heat. The gas valve control module monitors the output from the thermocouple or thermopile and records this fault when the signal falls below the required threshold. It does not necessarily mean the pilot failed to light, only that the flame was not strong enough to produce an adequate sensor reading. Common causes include a blocked pilot tube, a dirty or oxidized sensor tip, or a wiring issue between the pilot assembly and the gas valve.
Can I fix the 1 short flash code myself on a Bradford White water heater?
Some causes of this code are accessible to a knowledgeable DIYer. Inspecting and clearing a blocked pilot tube, checking wire connections at the gas valve, and cleaning visible oxidation from the thermocouple tip are tasks that do not require specialized tools. However, working on gas appliance components carries risk, and if you are not comfortable with the process or the fault returns after basic checks, a licensed technician should complete the diagnosis and any parts replacement.
Is the 1 short flash code on a Bradford White water heater dangerous?
The code itself represents a detected performance issue rather than an active safety emergency. The control system recorded a weak pilot signal and will continue to attempt normal operation. However, an unreliable pilot signal can lead to ignition failures and unburned gas conditions, so the underlying cause should be addressed promptly rather than ignored. If you smell gas at any point, leave the area, avoid operating switches or electronics, and contact your gas utility.
Will resetting the water heater clear the 1 short flash code?
Resetting the unit may temporarily clear the displayed fault, but it will not correct the underlying condition that caused the weak pilot signal. If the root cause such as a blocked pilot tube, oxidized electrode, or damaged wiring is not resolved, the fault is likely to return during the next call for heat. Always address the physical cause before relying on a reset to restore normal operation.
How much does it cost to repair the weak pilot signal fault on a Bradford White water heater?
Repair costs vary depending on the cause. If the fix is a simple cleaning of the pilot tube or tightening a loose connection, the expense may be limited to a service call fee, typically in the range of $75 to $150. If a thermocouple, thermopile, or wiring harness needs replacement, parts and labor combined generally fall in the range of $100 to $300. More involved repairs involving the gas valve assembly can push costs higher.

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