The expansion vessel in our Baxi boiler has to be completely disconnected
and removed to gain access to the Schrader valve. Understandably, the
company that services the boiler is reluctant to do this on a regular
basis (even though on the one-and-only occasion it has been checked there
was no pressure and it had to be pumped up).

Is there such a thing as a flexible Schrader valve extension which could
be left permanently attached to provide more convenient access? It would
need to be at least 6" long.

Richard.
http://www.rtrussell.co.uk/