what to put in a central heating system and how

[Thunderchild]

I have decorated my house (I won't say re-decorated as the previous mess was hardly "decoration") so i removed all of the radiators. Now i put three back for the winter and refilled the system with just water as this whole project has taken me just over a year. Now that I'm ready to put the radiators back and refill the system once and for all what additive do I put in the system and how do I physically get it in there ?

[ChuckFickens]

Is it a sealed or vented system?

(so do you have a header tank for it in the loft?)

[Thunderchild]

I don't know, how do I tell ? it uses a modern combi boiler and does not have a header tank (I just threw the old one out from before the new boiler was fitted a year before I bought it)

[ChuckFickens]

If you've no header tanks at all it must be a sealed system and will have a fill loop under the boiler with a tap on the pipe. make sure all drain a bleed valves in the system are shut Open the tap on the fill loop until the pressure gauge on the boiler reads about 1 and a quarter bar, goto the first rad and open the bleed valve until water comes out the valve and then shut it, go back the the fill tap on the boiler and open it until pressure gets back to 1 and a quarter then bleed the next rad, then back to the fill tap and so on until all rads are bleed.

You should put a rust inhibitor in the system, goto a plumbers merchant and ask them for a rust inhibitor before filling the system and tell them it's for a sealed system and follow the directions on how to get it in the system before filling.

[Thunderchild]

so the rust inhibitor comes with instruction and equipment required ?

[ChuckFickens]

Yes.

You normally remove a bleed valve totally and squirt it into the hole before filling the system. the amount to add will depend on how large the system is so read the instructions.

[mrpeter]

If you have a towel radiator and the bleed valve is on the top as I have then I put the inhibitor in that way. Nice and handy and no mess.

[heathfield]

Mrpeter's suggestion is good. Otherwise you'd probably need to get a small plastic funnel with 6'' or so of suitably sized plastic tubing attached to be able to get the inhibitor from the bottle into the radiator bleed valve.

[AlBags]

Fernox Sentinel .. or similar.

[eastern]

Buy some fernox or similar from DIY or plumbers merchant and put it into one of the radiators as you refill the system, try not to spill it as it stains woodwork!

[Thunderchild]

yep, i am now refilled and fernoxed up, I put the rust inhibitor and the boiler silencer in and am happy to have a complete and working system again that I can just turn on come winter