Advice on fitting TRV's and adding inhibitor to system

[600rob]

http://www.screwfix.com/p/drayton-trv4-white-chrome-trv-15mm-angled-l-s/34362


Im going to buy and fit some of these new trv’s and lockshileds this weekend and have a couple of questions:

I will be replacing the rad tails and compression fittings with the new ones that come in the box.

With all the joints/olives being new is it still recommended to use a joint sealing compound such as fernox lsx or boss white? (if so which is best)

Once all the valves are fitted and the system is re filled ill need to add some inhibitor.

Is there much difference in the type of inhibitor I use and how much inhibitor would you recommend for a system that comprises of 2 double rads, 1 single rad and a towel rail?

Cheers

 

[600rob]

Any suggestions?

 

[Plumber90]

Normally a bottle of fernox is good for a system with 10 radiators so you will be covered with one of them. You say you are going to change the radiator stems aswell so you will need ptfe tape for these and not a jointing compound.

 

[600rob]

Cheers plumber90.

I already have the ptfe tape for replacing the radiator tails in the rads.

My question about using a joint compound was referring to the joint(s) between the actual valve and the union nuts.
(The joints that comprise of a nut and olive)

 

[45yearsagasman]

A smear of lsx will be ok, but I prefer a jointing compound called Jet Blue. A smear of that round the olive will give you a good joint. Available at plumbers merchants. Fernox water hawk is also good.

 

[PotatoHead]

If you can get away with it I wouldn't bother changing the nut on the copper pipe going into the TRV/lockshield. You normally find the olive has been compressed to much to get off anyway. You can only re-use if the nut and inserted distance match. Same for the tails in the rad if they are really tightly wound in.

I find a jointing paste works best on the olives, I use Jet Blue as already mentioned.

If pipework drops to the radiators you are much better off fitting drain off lock shields rather than the standard ones. I fit them to all radiators to make isolating and removing much easier.