High
F.24 on Vaillant Ecomax Condensing 600/800 series

Your boiler is struggling because it does not have enough water circulating inside it, causing the system to heat up much faster than it safely can.

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

Water level low, Temperature rises too fast, Pump obstructed, pump running at lower capacity, Air in appliance, system pressure too low, flow and backflow NTC reversed

From this model's manual
Verified against the Vaillant/Vaillant Ecomax installation & service manual, page 49.
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

F.22View →F.23View →

All 90 fault codes on the Ecomax Condensing 600/800 series

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

d.0d.1d.2d.5d.7d.8d.10d.11d.13d.14d.16d.22d.23d.24d.25d.34d.35d.40d.41d.44d.46d.47d.60d.61d.67d.68d.69d.71d.72d.73d.80d.81d.82d.83F.0F.1F.10F.11F.13F.20F.22F.23F.25F.27F.28F.29F.32F.60F.61F.62F.63F.64F.65F.67P.1P.2P.5S.0S.1S.2S.3S.4S.5S.6S.7S.8S.10S.11S.13S.14S.15S.16S.17S.20S.21S.23S.24S.25S.26S.27S.28S.30S.32S.34S.36S.37S.39S.53S.54

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