BoilerFaultCodesWorcester Bosch No code displayed Fault Code
Also written as NOCODEDISPLAYED — same fault.
The Worcester Bosch No code displayed fault code means: your boiler has likely overheated because the gases exiting the system are too hot, causing a safety sensor to automatically shut it down.. It appears on 1 Worcester Bosch model in our database.
Technical description: Flue gas temperature limiter has triggered.
What causes the Worcester Bosch No code displayed fault?
This fault occurs when the internal safety sensor detects that the exhaust gases are reaching dangerously high temperatures, which can damage the boiler's internal components. The most common reasons for this are a build-up of debris or limescale inside the heat exchanger blocking heat transfer, or a lack of water flow preventing the system from cooling down properly.
This issue often comes to light during the first cold snap of winter when the boiler is suddenly required to run at full power for several hours to heat a cold house.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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Search the official register for a qualified engineer in your area.
Gas Safe Register →Worcester Bosch models that show the No code displayed fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Worcester Bosch No code displayed fault code information on this page is sourced and cross-checked against the official Worcester Bosch service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026