Refilling the fresh water tank

Gnash58

Hi all. Its coming round to the time I will be refilling the fresh water tank  on my M/H. Any hints/advice would be appreciated. I'm pretty ok with the facts about keeping taps and shower open but not sure what to do about the heating valve. I would think
that this has to be open also then closed when the system is full. But is there any "bleeding" that has to be done? How do I stop an air-lock in the heating system?

Cheers, Gary