Valiant boiler water pressure

[Gill]

Our Valiant boiler water pressure is low (way low - down to 0). We've topped it up before - know where the tap is etc, but it's so long ago that I can't remember:
Do we have to turn the boiler off first or let it cool down etc.?

 

[bosshogg]

No you don't need to turn off your boiler.
Have a look at this
http://http://www.askabuilder.co.uk/plumbing/bleeding-central-heating.html
You should get a good idea from it...bosshogg

 

[petej]

If you fill the system up whilst it is hot you never know what pressure it wall fall back to when it has cooled down. So ideally fill to approx 1 bar when cold.

If filling loop is remote it could be anywhere but usually by the boiler look for a silver coloured flex with valves on each end.
If it is built in then look under the boiler where all the pipes go in and you should see a thin flexi pipe there or even a very thin copper pipe.