Worcester Bosch · Greenstar Highflow CDi ErP

b4 boiler fault code

Greenstar Highflow 440CDi ErP & 550CDi ErP

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What b4 means

Data error.

Gas Safe engineer: Contact a Gas Safe registered engineer for diagnosis.

If you smell gas, a CO alarm sounds, anyone feels unwell, or there is an unsafe flame, leave and call 0800 111 999 from outside.

Renting? Report it to your landlord or housing provider first. They are responsible for gas safety and boiler repairs, and the repair should not cost you.

Safe check

Note the code shown on the display. Do not open, adjust or repeatedly reset the boiler. Contact a Gas Safe registered engineer.

When to contact an engineer

Contact a Gas Safe registered engineer for diagnosis.

Source and provenance

Greenstar Highflow 440CDi ErP & 550CDi ErP Installation, commissioning and servicing instructions 6 720 818 077 (2016/04) · §7.5 Fault finding Table 17, code b4, printed p. 47
installation, commissioning and servicing instructions
2016/04