BoilerFaultCodesWorcester Bosch DHW light Fault Code
Also written as DHWLIGHT — same fault.
The Worcester Bosch DHW light fault code means: your boiler has automatically turned itself off because the hot water inside it has become dangerously hot.. It appears on 3 Worcester Bosch models in our database.
Technical description: Over temperature shut-down if DHW temp water temperature above 85°C
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
Find a Gas Safe engineer
Search the official register for a qualified engineer in your area.
Gas Safe Register →Avoid the next call-out bill
A cover plan would handle faults like DHW light: no call-out fees, no surprise bills.
Affiliate links. We may earn a commission at no extra cost to you.
Worcester Bosch models that show the DHW light fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Worcester Bosch DHW light fault code information on this page is sourced and cross-checked against the official Worcester Bosch service / installation manuals for each affected model.
- Worcester Bosch 28 i SI manual (PDF)
- Worcester Bosch 28 Si RSF manual (PDF)
- Worcester Bosch Greenstar 25Si manual (PDF)
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026