Gledhill boilermate 2000?

Short answer no.
It could actually be quite dangerous to attempt!

The cylinder (being thermal store) would require a much larger expansion vessel than that of a normal combi type system.

The cylinder also may not handle being pressurised as it's design is that of an open vent type.

Basically, you would need to consider buying a sealed system thermal store cylinder such as an IMI tribune or similar, designed for the purpose, rather than try to adapt a possibly unsuitable cyclinder.

Carefree
July 2010