Your boiler is displaying a configuration setting rather than a breakdown, indicating the internal pump is set to its standard minimum operating speed.

To set the minimum CH pump speed to 70% (default)

What causes this fault?

This code appears when the boiler is being programmed to its standard factory setting for how fast the internal pump should circulate water. It is not an error or a component failure, but rather a confirmation that the pump will run at a minimum of 70% speed during heating cycles. You will usually only see this during commission or if someone has been adjusting the installer settings.