Boiler shows A25, burner locked out, gas supply appears normal

This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.

If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.

Possible Causes

Internal failure of Herz gas valve, stuck safety shutoff, wiring fault to gas valve coil, incorrect gas valve voltage

Safety: Gas valve work must be done only by licensed gas technicians.

Check supply voltage: A technician should verify correct voltage at the gas valve during ignition attempt.
Inspect connector: Ensure the gas valve plug is fully seated and wires are not damaged.
Do not tap valve: Do not attempt to free a stuck valve by hitting it; this can damage the safety mechanism.
Replace valve: If the valve does not open when commanded, replace the Herz gas valve and perform full tightness and combustion checks.

Professional Required 5/5

Herz gas valve

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