Low
C0 on Zanussi Ultra Combi

Your boiler has detected a minor internal communication error and needs to be restarted to clear the fault and resume normal operation.

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

Restart BOILER

From this model's manual
Verified against the Zanussi Ultra Combi installation & service manual, page 54.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

What causes this fault?

This fault occurs when the small memory chip that stores the boiler's identity fails to communicate with the main control board. The most common reason is a physical connection failure or a software glitch that causes the boiler to lose its configuration settings, rendering it unable to operate safely.

DIY fix possible

Locate the reset button or dial on the front control panelPress and hold the reset button for 3 to 5 secondsWait 2 minutes for the system to cycle and check if the error code clears

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Related fault codes

C1View →C2View →

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