High
E24 on Biasi Antares 25C M300V.2025 SM

Your boiler has safely shut itself down due to a safety lock-out, meaning it needs to be manually reset or checked by a professional.

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

Appliance lock–out

From this model's manual
Verified against the Biasi/Biasi Antares Combi installation & service manual.
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.

Find a Gas Safe engineer
Search the official register →
Boiler cover options

Avoid the next call-out bill

A cover plan would handle faults like E24: 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.

Related fault codes

E02View →E04View →E05View →

All 80 fault codes on the Antares 25C M300V.2025 SM

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

1+2+3+4+5+6+7+8+10 +11 +12 +13 +14 +15 +16 +18 +19 +20 +21 +22 +23 +24 +25 +26 +40 +42 +44 +50 +62 +65 +68 +77 +78 +79 +89 +91 +9696 +9799E01E02E03E04E05E06E07E08E10E11E12E13E14E15E16E18E19E20E21E22E23E25E26E40E42E44E50E62E65E68E77E78E79E89E91E96E97E99L1

Related guides you might find useful

Boiler keeps cutting out

Lockout fault with a reset-needed pattern.

Read →

Pilot light keeps going out

Older boilers: thermocouple, draught or gas supply.

Read →

When to replace your boiler

7 signs repair isn't worth it anymore.

Read →