Can I fit a new loop to my 100e that has a tap at both ends? The current one has a tap at the inlet and a non-return valve at the other. The problem is that it occasionally seeps into the boiler and over flows. With my original double tap I did not have this problem. Is it just a question of turning off the mains to fit the new one or do I have to empty the system?

Rod Hawkins, January 2010

Yes, although it should really have a none return valve on.

Henry, January 2010