BoilerFaultCodesWhat the manual says
Manufacturer manualFlow temperature target value
What causes this fault?
This code appears when the boiler's internal computer calculates the specific temperature it needs to send to your radiators to meet your heating demands. It is physically triggered by the system's sensors and controls communicating the required heat level based on your thermostat settings. Because this is a standard status update rather than a failure, your boiler will continue to operate as normal.
DIY fix possible
Check if your thermostat or external controls are set higher than the current room temperatureWait for the boiler to complete its current heating cyclePress the 'i' button to exit the diagnostic information menu if you entered it accidentally
Avoid the next call-out bill
A cover plan would handle faults like D.40: no call-out fees, no surprise bills.
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Related fault codes
All 135 fault codes on the ecoTEC plus 612 R1 VU GB 126/3-5
Seeing a different code? Every code this model can display, in one place.