Emergency
Explosive ignition on Worcester Bosch WR325 RSF

Your boiler is struggling to light smoothly, causing it to build up a small amount of gas before igniting with a loud bang.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Act immediately

Turn off your boiler and stop using gas appliances. Call a Gas Safe engineer now. This fault can be dangerous if ignored.

Technical description

Reduced pilot flame or Faulty slow ignition valve

Engineer required

This is a emergency 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 →

Related guides you might find useful

Pilot light keeps going out

Older boilers — thermocouple, draught, gas supply.

Read →

Boiler keeps cutting out

Lockout fault with a reset-needed pattern.

Read →

When to replace your boiler

7 signs repair isn't worth it anymore.

Read →