BoilerFaultCodesWhat the manual says
Manufacturer manualFLOW THERMISTOR FAULT
What causes this fault?
This fault occurs when the boiler's internal computer stops receiving a reliable signal from the sensor that monitors the temperature of the water being sent to your taps or radiators. The most common reason is that the sensor itself has developed a physical defect or the electrical wiring connecting it to the main control board has become damaged or loose. Without this data, the boiler shuts down as a safety precaution to prevents it from potentially overheating.
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 F 04 OR L 04: no call-out fees, no surprise bills.
Affiliate links. We may earn a commission at no extra cost to you.