Worcester Bosch · Greenstar 4000 Combi
353 boiler fault code
Greenstar 4000 Combi (GR4700iW C)
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What 353 means
The official Greenstar 4000 Combi manual classifies code 353 as a normal operating message, not a fault. See the linked table for the manufacturer's display description.
Safe check
Make a note of the displayed code. Do not remove the boiler casing or inspect internal gas, electrical or combustion components.
When to contact an engineer
The manual describes this as an operating message, not a fault. If the boiler is not operating normally or a separate fault appears, follow the user guide or contact a Gas Safe registered engineer.
Safety notice
A boiler fault code alone is not a gas or carbon-monoxide emergency. 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.
Source and provenance
- Greenstar 4000 Combi Installation Manual · 6 720 891 161 · §10.1.2 Operating/Fault code table, code 353, printed p. 74
installation and maintenance instructions
2021/10 · listed for appliances manufactured from 01/10/2023 onwards