Low
E091 on Vokera Synergy 25C

Your boiler has reached a set operating milestone and is reminding you that its main heat exchanger is due for a routine service and cleaning.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Monitor it

This is a minor fault. Keep an eye on it and mention it at your next annual boiler service. Reset the boiler and see if it clears.

What the manual says

Manufacturer manual

The boiler has an auto-diagnostic system which, based on the total number of hours in certain operating conditions, can signal the need to clean the primary exchanger

From this model's manual
Verified against the Vokera/Vokera Synergy Combi 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 fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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All 53 fault codes on the Synergy 25C

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

CFSCOME010E011E012E013E014E015E020E021E030E031E032E033E034E035E036E037E038E039E040E041E042E050E051E052E055E056E060E065E070E071E072E075E077E080E081E082E088E090E092E093E094E095E096E097E098E099FILFWEROBCDSFS

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