John Wood electronic gas water heater shows E012 and will not ignite; igniter does not glow or spark

Safety: Turn off gas and power before handling the igniter. Igniters are fragile and can be very hot.

• 1. Visual inspection: Remove the burner access cover and locate the igniter. Look for cracks, breaks, or heavy deposits on the igniter element.
• 2. Test continuity: Disconnect the igniter leads and measure resistance. A hot surface igniter typically has a specific resistance range; an open circuit means it is failed. Spark igniters may show low resistance.
• 3. Check wiring: Inspect the igniter wires for heat damage or loose connections at the control board and igniter.
• 4. Replace igniter: Install the correct John Wood replacement igniter, avoiding contact with the element surface. Route wires away from hot surfaces.
• 5. Control board check: If a known-good igniter does not receive power during an ignition attempt, the control board's igniter circuit may be defective and require replacement.