BoilerFaultCodesWhat the manual says
Manufacturer manualParameter storage unit (PSU) error
What causes this fault?
This fault occurs when the boiler's internal memory chip fails to communicate with the main control board, similar to a corrupted file on a computer. It is usually caused by a hardware failure within the chip itself or a loose physical connection on the circuit board that prevents the boiler from reading its essential operating instructions. Because the boiler no longer knows its own safety limits or settings, it shuts down immediately as a precaution.
Engineer required
This is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
Avoid the next call-out bill
A cover plan would handle faults like 5 Red Flashes: no call-out fees, no surprise bills.
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