Two questions - TRVs and central heating inhibitor

[Pineman]

1) I want to replace the (old) single radiators in my house with new double ones, and also fit TRVs in place of the existing valves. Should I put TRVs in every room or leave one or more room without?

2) How do I go about adding inhibitor to the system once the work is done? I have a combi boiler and a sealed system. As I understand it I can add inhibitor via a bleed valve, but how do I get it into the valve? Also, does it matter which radiator it is added to or can it be added to any?

 

[bengasman]

You can fit trv's on all rads, apart from the room with the roomstat, which is best fitted with 2 lockshields.

It doesn't matter where you put the inhibitor in the system, do what is easiest. Towel rail is a good choice if you have one.

 

[Pineman]

Thank you. Just one more thing - what do I use to physically add inhibitor to a radiator, some sort of tubing and funnel?

 

[bengasman]

I use a pump and take my pick from a set of adapters, but if you don't have access to that, use whatever makes life easy.
And use quality inhibitor, not any of the crap from diy sheds.