How do I know if I have an open vented or a pressurised system?

[littleredsquirrel]

Looking to install a woodburning stove and I'm toying with the idea of one with a back burner.

if you have a pressurised system there will most likely be a pressure gauge on the front of your boiler, possibly behind a flap. It will be graduated in BAR and the arrow will probably be somewhere between 1 and 1.5.

Thanks pigletjohn. I will get DH to have a look this evening!