BoilerFaultCodesWhat the manual says
Manufacturer manualCurrent primary water temperature higher than set value
What causes this fault?
This fault occurs when water is staying inside the boiler's heat exchanger for too long, causing it to overheat beyond the safe limit. The most common reasons are a pump failure that prevents water from moving around your radiators, or a blockage such as trapped air or sludge that is restricting the flow. Because the heat cannot be carried away from the boiler quickly enough, the system shuts down as a safety precaution.
This issue is more common during the first cold spell of autumn, when pumps that have sat idle all summer can seize up or struggle to restart.
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 204 O: no call-out fees, no surprise bills.
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