Radiator TRV fitting problem/Question.

[Don72]

I've been going through severe problems with my Heatline Compact S30

combi-boiler and recently had an engineer out to it under warranty. H

noted that the TRV's the instaler had fitted were one-directional, sai

this would cause knocking and stress on the boiler and advised that they be changed to bi-directional. He also advised a room-stat which the installer also neglected.

I have drained the system and bought new Mistral bi-directional TRV's (with self seal tail). Here's where I am confused. The valve section allows the tail to move freely and does not appear to seal at all. Al

that is in the boxes are a two-way valve, two brass o-rings, two nuts and the sliding tail. I bought from PlumbBase, but I found the same item on ebay just now and it appears to have an extra brass part that did not come with the units I purchased. Am I missing parts from these or am I failing to realise how they work How is the tail sealed in?

Also, the previous fitting had a female coupling on the bottom and th

copper pipes seem to be attatched to what I presumed was the old bras

o-rings! They rotate, but would probably need cut off or an awful lo more force than I would expect. Unless I can get these off, the ol fitting nut wont come off, and I cannot fit the new parts anyway. An help would be gratefully appreciated. Thank you in advance

-- Don72

[Don72]

I have posted pics of my problem at my photobucket account.

[chris French]

In message , Don72 writes

One thread is enough - I've replied there.

[Set Square]

You should certainly have a room stat - and the radiator nearest to that shouldn't have a TRV at all.

With regard to bi-directional TRVs, you've only got half the story! Very few TRV are truly bi-directional - in that they don't *care* which way the flow goes. But many are configurable - in that there's a little gizmo to turn to make them work in one direction or the other.

If the flow through your existing TRVs is in the wrong direction, the simplest solution is to move them to the opposite end of the radiator rather than buying new ones.

With regard to the new TRVs, as far as I can see from your photos (doesn't your camera have a focus adjustement?!) the TRV has a compression fitting both ends - so either end can connect to the supply pipe, with the other end connecting to the radiator tail. So the brass O-ring to which you refer is simply a compression olive, and the radiator tail is, in effect, a piece of

15mm pipe onto which you tighten the compression fitting. [It may be this which makes it bi-directional - requiring you to have the thermostatic bit vertical for one direction of flow and horizontal for the other direction]. Didn't the valves come with an instruction leaflet?