Fitting TRV's

[robulon]

Hi,

I'm looking to fit TRV's on the existing radiators in my house but am struggling a little bit. I have bought the TRV's from a well know DIY retailer and the instructions on the pack say to screw the half inch BSP tailpiece into the radiator tapping (which is on the left hand side of the picture).

My question is, due to the fact I am wanting to use the existing pipework, by using the tailpiece, I am making the valve bigger than the old one so the pipes may not be positioned correctly. If I didn't fit the tailpiece the valve looks like it would be a direct replacement for the old one. So is the tailpiece an essential part of the valve? I would assume it is because they wouldn't put it in otherwise but hopefully someone with a bit more sense and knowledge than me can advise?

Many thanks,
Rob View media item 49106

 

[Armo74]

Are your existing tails 1/2" or 3/4"? Do not fit a trv in the same room as your room stat if you have one.

 

[Dan Robinson]

And if you don't have a room stat, fit one before you start monkeying about with trvs.

 

[robulon]

the existing tails are half inch. all this tail piece seems to do from wwhat I can see is make the valve longer. i've also looked at guides for fitting them online and none of the ones i've seen mention a tailpiece

 

[Dan Robinson]

Post a picture of your existing valves. I think you have 3/4" unions.

 

[willsgas]

I think you are confusing the old rad tail as part of the rad.

Those tail pieces in the pic go into a new rad (as new rads are not supplied with them) or replace old ones.

I personally would replace them as it looks cleaner, but you don't have to.

If you do take the old ones out you will need some ptfe or locktite 55 to seal the new threads.