Medium
12 on Ideal Maximiser SE 42

Your boiler is temporarily shutting down because too many of your radiators are turned off or blocked, restricting the flow of water.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Book a service

This fault should be looked at by a Gas Safe engineer within the next week or two. It may get worse if left.

What the manual says

Manufacturer manual

Too few radiators are open or the differential pressure switch is not properly adjusted.

From this model's manual
Verified against the Ideal/Ideal Maximiser Se installation & service manual.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

DIY fix possible

Check all your radiators around the house and make sure at least most of them have their valves fully open.Ensure individual radiator thermostatic valves are not jammed shut.Reset the boiler using its reset button once the radiator valves are open.

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Related fault codes

F12View →LCView →P1View →

All 40 fault codes on the Maximiser SE 42

Seeing a different code? Every code this model can display, in one place.

- / A- / H- / Y= / H4 / A111314151617181920212223242526272829303132333435363738394041424344E / F

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