High
AL 83 on Sime Murelle One HE

Your boiler is having trouble burning gas correctly, which is likely caused by air in the pipes or a dirty internal sensor.

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

Irregular combustion (temporary error) — bleed air from gas circuit; check electrode; check flue/outlets clear; check calibration

From this model's manual
Verified against the Sime Murelle One He installation & service manual, page 43.
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

AL 01View →AL 02View →AL 05View →

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