Red Westie wrote:TWO TANKS......
Top tank with the DARLEK pressure cap (should be full to the brim)
The lower expansion tank (the one you can see behind the number plate flap) the level should be between Min ans Max. This has a plain cap.
it can get confusing... so a lot of us use the term top up tank and expansion tank
as the names suggest they do what their name says .. the expanding water flows into the top up tank