Heater shows F07 and will not fire; may occur after a power surge or storm.

Safety first: Turn off power at the breaker before accessing the control compartment.

• Power cycle: Turn off the heater at the breaker for at least 2 minutes, then restore power. Sometimes F07 clears after a full reset.
• Inspect wiring harnesses: Remove the front panel and locate the main control board and display/interface board. Gently reseat all plug-in connectors, ensuring they are fully engaged and not corroded.
• Check for surge damage: Look for burn marks, swollen components, or a burnt smell on the control board. If present, the board is likely damaged.
• Verify external controls: If the heater is controlled by an external automation system, disconnect the remote control wires at the heater terminal strip and try operating the heater in standalone mode. A wiring fault in the automation line can trigger communication errors.
• Board replacement: If F07 persists and wiring is intact, the main control board or display board may need replacement. This should be done by a qualified technician to ensure correct configuration.