This appliance has a range of maintenance settings which allow the installer / service engineer to set parameters for when the appliance will put up reminders for servicing or to trigger error codes to prompt an engineer maintenance visit.
These can be set in the service/installer menu.
To access this press and hold the tap and radiator buttons simultaneously for 3 seconds then select: "Settings" > "Maintenance"
The parameters that can be set are as follows:
Without (no maintenance reminders or error codes should be displayed).
Boiler run time (the time the appliance has been powered on for but not necessarily running for).
Burner on time (the time the burner has been lit for).
Landlord (this allows end dates, reminders and installer details to be entered) - please note that if this setting has been used and the maintenance date has been exceeded by more than 14 days then the appliance may have been set to reduce the DHW flow temperature to 35°C maximum or the DHW and CH functions disabled.