Drained CH, should I have put additives in?

[Anticyclone]

I drained and refilled the central heating a little while ago, and it's just struck me that maybe I should have added something to the water to help with rust prevention or efficiency or something? Should I? Is damage being caused by lack of additive in the system?

It's a closed combi boiler system on a small 7 radiator house.

A sealed system (pressure gauge in the boiler, no feed and expansion tank in the loft) is not so prone to corrosion as an open one, but yes, you should have added a corrosion inhibitor such as Sentinel X100. It will cost you about £15 in Screwfix.

If you are in a hard-water area there are additives to reduce limescale, and if it is a new boiler on old radiators, you ought to have a system filter to capture corrosion particles, and you can get an additive to loosen old sediment.

Thanks PG, I'll buy that X100 stuff. We are also in London so hard water additive seems sensible too. Boiler and radiators are less than 10 years old so OK on that front.

Sentinel X200 is for limescale. You put it in and leave it in. It is difficult to add chemicals to a sealed system once it is full, so go to their website and look at the Concentrate Dosing products.