High
AL 62 on Sime Brava Slim HE System

Your boiler needs to run a self-check to ensure it is burning gas safely and efficiently, usually following a repair or a change in gas supply.

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

Self-calibrating procedure is required — execute self-calibration procedure (required after gas valve, electrode, burner or fan replacement)

From this model's manual
Verified against the Sime Brava Slim He installation & service manual, page 33.
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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