Low
S.34 on Heatline CaprizPlus 24a

Your boiler has detected very cold temperatures and has automatically turned itself on to prevent the internal pipes from freezing.

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

"Frost protection" mode

From this model's manual
Verified against the Heatline Caprizplus 24a installation & service manual, page 26.
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 that your external condensate pipe is not frozenEnsure your thermostat is turned up to a normal levelMonitor the boiler until the S.34 code clears, which happens automatically once the temperature rises

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