BoilerFaultCodesTechnical description
Activation of maximum ELTA T protection
What causes this fault?
This fault occurs when the boiler's internal sensors detect that the heat is increasing much faster than the water can carry it away. The most common reason is a restriction in water flow, often caused by a failing pump or a build-up of sludge and debris blocking the narrow pipes inside the heat exchanger.
This issue often surfaces in autumn when the heating is turned back on after a long summer break, as pump components can seize or sludge can settle during periods of inactivity.
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.
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