What the manual says
Manufacturer manualPump over run
What causes this fault?
This status occurs when the boiler is trying to move excess heat away from the internal heat exchanger after you have finished using hot water. It usually happens because the water isn't circulating quickly enough through the internal bypass or the pipes to cool the system down. The most common reasons are a pump that is starting to struggle or a slight internal blockage that restricts the flow of water.
Engineer required
This fault requires 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 S.17: no call-out fees, no surprise bills.
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Related fault codes
All 77 fault codes on the ecoTEC plus 637
Seeing a different code? Every code this model can display, in one place.