Bradford White Water Heater Error Code 4 — Ignition Lockout Fix

Bradford White water heaters equipped with electronic ignition and the Icon System control display error code 4 (four slow flashes) when the unit fails to ignite after multiple attempts. This is called ignition lockout — the control has given up trying to light the burner after a set number of tries.

No hot water. The burner won’t fire. But the fix is often simple: a dirty igniter or a partially closed gas valve.

Jump to Fix

• What Error Code 4 Means
• Quick Reference Table
• Most Common Causes
• Step-by-Step Diagnosis
• Parts and Costs
• When to Call a Tech

What Error Code 4 Means

The Icon System control in Bradford White gas water heaters uses a hot surface igniter or spark igniter to light the main burner. The control sequence is: purge, spark, trial for ignition, flame sense. If the control doesn’t detect a flame within the ignition trial period — typically 7 seconds — it retries. After 3 failed attempts, it locks out and flashes error code 4.

Models affected: Bradford White gas water heaters with electronic ignition — Defender Safety System (DSI), high-efficiency, and power-vent models. This does not apply to standing pilot models (those use error code 1 for pilot outages).

The lockout must be manually reset by turning the gas control knob to OFF and back to the desired temperature setting.

Quick Reference Table

Most Common Causes

Always start by checking the gas supply — this is the simplest fix and accounts for many lockout calls.

Step-by-Step Diagnosis

Step 1: Reset the system

Before doing anything else, try a reset:

1. Turn the gas control knob to OFF
2. Wait 60 seconds
3. Turn the knob back to the desired temperature setting
4. Listen — you should hear the igniter clicking or glowing, then the burner ignite

If the burner lights and stays lit: The error was likely a temporary gas interruption or wind gust. Monitor for reoccurrence.

If error code 4 returns immediately: Proceed to Step 2.

Step 2: Check the gas supply

This is the most overlooked cause of ignition lockout. Confirm gas is reaching the water heater.

• Check that the gas shutoff valve near the water heater is fully open (handle parallel to the pipe)
• Check that the gas meter is active — try lighting another gas appliance (stove, furnace)
• If other appliances also won’t light, contact your gas utility — you may have a supply issue
• If you smell gas, leave immediately and call your gas utility from outside

A half-closed gas valve is a surprisingly common issue after kitchen renovations, meter work, or gas line installation.

Step 3: Inspect the igniter

Bradford White electronic ignition systems use either a hot surface igniter (glows red-orange) or a spark igniter (makes clicking sounds).

For hot surface igniter models:

1. Remove the burner access panel at the bottom of the tank
2. Watch the igniter during a start cycle — does it glow bright orange?
3. No glow: Check the igniter wiring and the gas control valve output
4. Weak glow or glowing but no ignition: The igniter may be carbon-fouled — clean with fine sandpaper or replace it
5. Glowing in the wrong position: The igniter bracket may be bent — the tip should be centered in the burner tube opening

The igniter gap should be approximately 3/16” to 1/4” from the burner surface. Use a feeler gauge to check.

For spark igniter models:

1. Listen for the spark clicking during startup
2. Look through the sight glass — do you see a spark at the electrode tip?
3. No spark: Check wiring and the spark module (may be inside the gas valve assembly)
4. Spark but no ignition: Check that the spark gap is correct (typically 1/8”) and the electrode isn’t cracked

Step 4: Clean the flame sensor

The flame sensor is a metal rod that detects when the burner is lit. If it’s dirty, the control shuts the gas valve even though the burner is firing.

1. Turn gas control to OFF and wait 5 minutes
2. Remove the burner assembly from the tank
3. Locate the flame sensor rod (usually mounted next to the burner)
4. Gently scrub the rod with emery cloth or fine sandpaper
5. Wipe clean with a dry cloth
6. Reinstall and test

A dirty flame sensor is the #1 cause of repeated ignition lockout on electronic ignition water heaters. This fix alone resolves about 50% of error code 4 cases.

Step 5: Check the burner and flue

Remove the burner assembly and inspect:

• Burner ports clogged: Use a vacuum and compressed air to clear debris
• Flue tube blocked: Shine a flashlight up the flue tube — if you can’t see light at the top, the flue is blocked
• Flame pattern uneven: Indicates burner damage or debris — replace burner if damaged

A blocked flue is dangerous — it can cause carbon monoxide to enter your home. If you find a blockage, confirm the issue is cleared before restarting the heater.

Step 6: Test the gas valve

If you’ve confirmed gas supply, a working igniter, a clean flame sensor, and a clear flue — the gas control valve itself may be the problem.

• The gas valve solenoid may have failed
• The internal regulator may not be passing gas
• The control board inside the valve may not be sending the open signal

Gas valve replacement is a licensed job in most areas.

Parts and Costs

When to Call a Tech

Call a licensed technician if:

• You cleaned the flame sensor and igniter and error code 4 still returns
• You suspect a gas valve failure
• The burner looks damaged or the flue is blocked
• You’re not comfortable working with gas components
• The error code returns repeatedly after resetting

Average repair cost with a technician: $150–$350 for igniter or flame sensor replacement. Gas valve replacement: $300–$600 installed.

Related Guides

• Bradford White Water Heater Error Code 1 — Pilot Outage Fix
• Bradford White Water Heater Error Code 5 — Flame Sense Circuit Fault
• Bradford White Water Heater Error Codes Complete Guide

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