BoilerFaultCodesWhat the manual says
Manufacturer manualWhen the Return Temperature > 80°C for 5s, the Slave board shuts down
What causes this fault?
This fault occurs when water is not moving through your heating system fast enough to carry heat away from the boiler, causing it to overheat instantly. The most common reasons are a failed internal pump that isn't pushing the water or a significant blockage within the boiler's heat exchanger. It can also be triggered by a faulty sensor that is incorrectly reporting a high temperature to the control board.
This issue is more common during the first cold spell of autumn when pumps that have been sitting idle all summer tend to seize up.
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 47: no call-out fees, no surprise bills.
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