High
D on Worcester Bosch 24/28/35 CDi MkII

Your boiler is failing to ignite or stay running when the heating is turned right up, which means you will likely have no central heating.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Call an engineer soon

Book a Gas Safe engineer within 24 to 48 hours. Your boiler may be unsafe or could break down completely if left.

What the manual says

Manufacturer manual

FAIL POINT D - With CH control knob fully clockwise, does the boiler ignite and appear to run normally in central heating mode?

From this model's manual
Verified against the Worcester Bosch/Worcester Bosch 24 28 35 Cdi Mkii Rsf 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.

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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Related fault codes

EAView →CEView →D5View →

All 27 fault codes on the 24/28/35 CDi MkII

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

ABCEE00 716E00-711E00-716E00-720E00-721E00-730E00-737E00-738E00-741E01 612E01-840E80-450E80-451FGHIJKtaehrevO yramirPtluaF rosneStuokcoL renruB

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