High
ÿ9 on Remeha Avanta 18V

Your boiler has shut itself down because it cannot move water around the system fast enough, causing it to overheat rapidly.

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

Lock-out; maximum temperature rise exceeded, dT between supply and return ≥ 22°C, rate of rise > 2,7°C/sec, no through flow, insufficient water, or shut down input activated

From this model's manual
Verified against the Remeha Avanta 18v 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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