Which "additive" for my central heating system

[spyke749]

Hi,

I have :
Saunier Duval Enviro Plus F28 System boiler
Range Tribune HE Non vented hot water cylinder
Plastic push fit plumbing for majority of CH pipe runs
Normal radiators on copper tails between the radiators and plastic piping
TRV's on the radiators

All fitted in new build house 5 years ago.

The system has been drained by at least 50% and will be re-filled this weekend.

I live in leicestershire in a very hard water area.

What treatment would you recommend I add to the central heating system when I re-fill?

Am I ok to add "product" to a half full system and re-fill, or, should I drain the rest of the system down and start from fresh?

Advice appreciated.

 

[linkyplumb]

Sentinell X100 or Fernox F1 should see you right

 

[spyke749]

done some research ... Sentinal X100 it is. Thanks