ALARM 06 High

Sime ALARM 06 Fault Code

Also written as ALARM06 — same fault.

The Sime ALARM 06 fault code means: your boiler has tried to start but could not detect a flame, likely because gas isn't reaching the burner or the ignition spark is failing.. It appears on 2 Sime models in our database.

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.

Technical description: Ignition lockout — flame not detected; press reset; check gas supply and electrode
Typical repair cost £100-£250 (including labour)

DIY fix possible

Press and hold the 'R' or reset button to see if the error clears.Check that your gas meter is in credit and that other gas appliances like a hob are working.Verify that the gas isolation valve under the boiler is fully open.

Find a Gas Safe engineer

Search the official register for a qualified engineer in your area.

Gas Safe Register →
Boiler cover options

Avoid the next call-out bill

A cover plan would handle faults like ALARM 06: no call-out fees, no surprise bills.

Approved partner
Domestic Appliance Guard
Unlimited call-outs, 24/7 helpline, no price-hike promise
Get a quote →

Affiliate links. We may earn a commission at no extra cost to you.

Sime models that show the ALARM 06 fault code

Click a model for the full fault code list and model-specific repair notes.

Source

Sime ALARM 06 fault code information on this page is sourced and cross-checked against the official Sime service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026