central heating

[wullie]

Header tank for radiators required top up what do I use I have been told ionized water correct and what about antifreeze type please.

[Tiggs]

If I remember right there are two main sorts of anti-freeze and you should not mix them. So if you don't know, just add water for now.

[IDS]

I always use tap water for our gas boiler (just like domestic systems), but other fancy boilers may specify otherwise. Your antifreeze choice is blue or pink, use whatever is in there already, and premix with water to the required concentration before you add it.

More importantly if the header tank requires filling, you have a small leak somewhere, now is the time to look for it.

[Joe the plumber]

There are also un-coloured anti-freeze mixtures with inhibitor available specifically for central heating, eg:

 

http://www.screwfix.com/p/no-nonsense-central-heating-inhibited-anti-freeze-5ltr/74586?_requestid=35689

 

If you've got the chance, I'd be inclined to drain and flush it and start again so you know exactly what you've got in there.

Incidentally, if you've got soldered joints on the system, you're not supposed to use 'OAT' type antifreeze.