The DHW expansion vessel seems to be full of water when the car tyre type valve on the top of it is depressd. As I have other work to do on the boiler I decided to change this vessel as well, as it is not too expensive.
The manual with the boiler explains how to change the vessel but there is no mention of what pressure it should be set to. (My DHW system just outputs from the boiler to the hot taps).
What should the pressure be set to and what is the procedure for pressurising the vessel?