BoilerFaultCodesWhat the manual says
Manufacturer manualFlow sensor above 95 °C
What causes this fault?
This fault occurs when the water leaving the boiler gets too hot, causing the system to shut down to prevent damage. The most common reason is a lack of water flow, often caused by a failing pump or a blockage in the pipework that prevents heat from being carried away from the boiler quickly enough.
This issue is more frequent during the first cold snap of autumn when heating systems are turned back on after sitting idle, which can cause internal pumps to seize.
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 b18: no call-out fees, no surprise bills.
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