Worcester Bosch · Greenstar 30i

9U boiler fault code

Greenstar 30i combi

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What 9U means

Internal error — control box or HCM defective or loose (9U 233).

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 and any three-digit cause code shown. Do not remove the casing, adjust anything or keep resetting; contact a Gas Safe registered engineer.

When to contact an engineer

Contact a Gas Safe registered engineer for diagnosis.

Source and provenance

Greenstar i ErP (25i/30i combi) Installation, commissioning & servicing instructions 6 720 806 944 (2016/07) · §8.1.2 Error codes, Table 48, printed p. 66
installation, commissioning & servicing instructions
2016/07