Ariston Main PCB Power Supply / Low Voltage Fault

Boiler shows 302, random resets, display flickers, sometimes loses settings

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

Faulty main PCB, Unstable mains supply, Loose power connections, Internal PCB power regulator failure

Safety: Isolate power before accessing electrical terminals.

Check mains supply: Ensure the boiler is connected to a stable 230V supply via a fused spur. Avoid extension leads.
Inspect terminals: Tighten all live, neutral, and earth connections at the boiler's terminal block. Loose connections can cause voltage drops.
Look for PCB damage: Signs of burning, bulging capacitors, or scorching on the main PCB indicate failure.
PCB replacement: If 302 persists and supply is stable, the PCB likely needs replacement by a qualified engineer.

Hard 4/5

Main Control PCB

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