Bradford White ICON Gas Control Replacement Procedure

Why this matters

The Bradford White ICON System gas control valve (used on Defender Safety System tanks from 2010 onward) integrates the thermopile-powered electronics, the gas valve, and the diagnostic LED into one assembly. When the LED blink code indicates control failure, replacing the entire ICON gas control is the only OEM-supported repair; field calibration or board-level swap is not authorized. A tech who arrives without verifying the failure code, the model number, and the LP-vs-natural gas variant of the replacement makes a second trip on every call.

Identify the ICON variant

ICON gas controls come in five variants. The replacement must match exactly:

• 239-44857-00: standard atmospheric natural gas (most common Defender)
• 239-44857-01: standard atmospheric liquid propane
• 239-46377-00: Power Vent natural gas (has the additional 6-pin harness for the blower)
• 239-46377-01: Power Vent LP
• 415-50571-00 / -01: Eco-Defender ultra-low NOx variants for California, Texas, and Utah

The model number is on the rating plate on the tank jacket. The fuel type is also on the rating plate, never assume from the customer's invoice.

Confirm the failure with the blink code

The ICON LED is on the front face of the gas control, visible without removing the burner door. Blink codes (current Bradford White service manual, document 41200H):

• Steady ON: normal, pilot proven
• 1 flash: normal standby, no call for heat
• 2 flashes: thermopile output low (under 400 mV DC open circuit, under 250 mV under load)
• 3 flashes: pilot not lighting; ignitor or gas supply issue
• 4 flashes: gas control internal failure; replace ICON
• 5 flashes: tank thermistor (temperature sensor) fault
• 7 flashes: low DC output to gas valve solenoid
• 8 flashes: gas valve solenoid open or shorted

Codes 4, 7, and 8 require ICON replacement. Code 2 may be solved by thermopile replacement alone (Bradford White part 239-45445-00, fits all ICON variants).

Pre-replacement verification

Before pulling the gas control:

1. Measure the thermopile open-circuit voltage with the pilot lit and the burner door open: spec is 600 to 850 mV DC. If under 400, replace the thermopile first; the gas control may be fine.
2. Verify gas supply pressure: 7 inches water column natural, 11 inches LP at the inlet of the gas control under flow. Inadequate supply pressure mimics control failure.
3. Verify proper venting on Power Vent models; a blocked vent triggers blower fault codes that the tech can confuse for ICON failure.
4. Confirm the tank is not under recall. Bradford White issued service bulletins on specific date-code ranges of the 239-44857-00 control; check the production date on the rating plate.

Tools required

• Adjustable wrenches up to 14 inch
• Gas leak detector solution (no leak detector spray that contains ammonia)
• Manometer or U-tube for gas pressure
• DC voltmeter capable of millivolt resolution
• Replacement ICON gas control matching the variant
• Replacement thermopile if voltage was low
• Replacement gas piping nipples if the existing nipples show paint or insulation contamination
• Pipe joint compound rated for natural gas and LP (Rectorseal T-Plus 2 or Loctite 565)

Step by step replacement

1. Turn the gas control knob to OFF. Wait 5 minutes for the gas inside the control to vent.
2. Close the gas supply shutoff at the appliance.
3. Disconnect the gas supply union upstream of the gas control. If no union exists in the supply, install one during this service (required by IFGC for serviceability).
4. Disconnect the thermopile lead from the gas control terminal. Note polarity; the thermopile is two-wire screw-terminal style; orientation does not matter for voltage but consistency matters for the next tech.
5. Disconnect the pilot tube (compression fitting on the gas control side) and the burner manifold tube (compression on the gas control outlet side).
6. On Power Vent models, disconnect the 6-pin harness to the blower assembly.
7. Disconnect the thermistor cable (small 2-pin plug on the side of the ICON).
8. Unthread the ICON from the tank. The gas control is threaded into the tank with a 3/4 inch NPT immersion connection. Use a pipe wrench on the wrench flats. Do not turn by the gas control body; it is plastic and will crack.
9. Apply pipe joint compound to the new ICON's NPT threads.
10. Thread the new ICON into the tank to factory hand-tight plus 1.5 to 2 turns for sealing. Final position must have the control knob and the inlet/outlet ports oriented correctly for the gas piping.
11. Reconnect the pilot tube, manifold tube, thermopile, thermistor, and (if applicable) blower harness.
12. Open the gas supply slowly.
13. Leak test every joint with leak detector solution.

Light pilot and verify

The ICON pilot lighting sequence is fixed:

1. Turn the gas control knob to PILOT and press down.
2. Press and release the white piezo igniter button repeatedly until the LED begins blinking, indicating pilot proven (typically 5 to 15 presses with a fresh thermopile).
3. Continue holding the knob depressed for 60 seconds after the LED blinks once. This warms the thermopile to operating voltage.
4. Release the knob. The pilot should remain lit; the LED transitions from 1 flash to steady or to the normal standby pattern.
5. Turn the knob to ON.
6. Set the temperature dial. Bradford White ships the ICON dial in the A position (approximately 120 F) by default. UPC and IPC require water heaters serving fixtures not used for bathing to be 110 F minimum at the fixture; for residential set 120 F to limit scald risk per ASSE 1016 mixing valve sizing rules.

References

• Bradford White ICON Service Manual, document 41200H (latest revision)
• ANSI Z21.10.1 / CSA 4.1 Gas Water Heaters Volume I Storage Water Heaters
• International Fuel Gas Code (IFGC) 2024 Section 624 Water Heaters
• ASSE Standard 1016-2017 Performance Requirements for Automatic Compensating Valves