BoilerFaultCodesWhat the manual says
Manufacturer manualDifferent temperature error
What causes this fault?
This fault occurs when the boiler's internal sensors detect that water isn't moving through the system correctly, leading to a sharp temperature gap between the flow and return pipes. The most common reasons are a failing circulation pump that can't push water around or a blockage in the heat exchanger caused by a buildup of limescale or sludge. In some cases, it may simply be a faulty sensor providing an incorrect temperature reading to the main control board.
This issue often surfaces in autumn when the heating is turned back on after a long summer break, as pump components can seize up from lack of use.
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 44E: no call-out fees, no surprise bills.
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