BoilerFaultCodesWhat the manual says
Manufacturer manualOperating mode
What causes this fault?
This code is triggered when the boiler enters a self-diagnostic or monitoring mode to check the temperature difference between its internal sensors. It often occurs if the boiler detects a rapid rise in heat and needs to briefly pause the burner to ensure water is circulating correctly. In most cases, it is a temporary state rather than a component failure.
DIY fix possible
Check if the boiler is set to a specific service or chimney sweep modePress the 'Reset' button to clear the temporary statusWait 15 minutes to see if the status clears itself during normal operation
Avoid the next call-out bill
Monthly cover means no unexpected bills when your boiler breaks down.
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Related fault codes
All 365 fault codes on the Greenstar CDi Compact
Seeing a different code? Every code this model can display, in one place.