Worcester Bosch Greenstar 8000 System Boiler Issues

[marshian]

3 hours ago, EinTopaz said:

 

There is a separate much older WB CDI boiler upstairs that does the hot water for all the property and some rads up there too. It's a conventional type that one. And the flow pipe coming out of it (using the same measuring tools) is always within a degree of the LCD display on that boiler.... I only wish the one downstairs was as straight forward.

The boiler we're discussing here with the problems solely does the CH for the ground floor, as to not complicate the older system. 

 

Ahhh that makes perfect sense although two boilers mean two service bill/maintenance costs and I'd be fretting about which one was driving the bills but that's me all over