TRV4 Rad Valves Leaking

I fitted new Drayton TRV4 radiator valves to all my rads about 4 years ago, and already two of them have started leaking where the valve pin projects from the valve body. Is this a common problem? Are they fixable or is the only solution to renew the whole thing? Anyone have a magic solution for doing this that avoids draining the system (it's an open vented system with a header tank)?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Tuesday, 17 September 2013 18:48:32 UTC+1, Davidm wrote:

Most valves have a gland nut on the valve body that can be tightened slightly to stop the leak BUT not too tight to stop the pin moving.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

No gland nut on thse valves, the operating pin just projects through a plastic insert in the top of the valve body (unless the nut is inside the valve body - which would be pretty useless anyway).
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload


It probably has an O ring. Some have PTFE packing. Supposing you can get one, they can be replaced but sometimes they still leak. It's quite unusual to leak so soon. Have you got inhibitor in the water? Could be a corrosion problem. You'll likely end up replacing them. May as well wash the system out and make sure you have inhibitor in. Many inhibitors claim to have lubricators as well.
It's a good idea to "exercise" the valves by winding open and closed now and then. (Keeps the spindle clean)
The best valves BTW have a bellows not an Oring.. Expensive.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Tue, 17 Sep 2013 20:20:24 +0100, "harryagain"

Yes system has inhibitor in. I fitted the new TRV's just before a new boiler was installed, and the whole system was power flushed at that time (by the boiler installer - qualified plumber).
Looks like I'll just have to replace them. Exercising the valves is a good tip - thanks.
I did look at the more expensive valves - OUCH! Even the TRV4s are quite a bit more expensive now than when I bought the last lot.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 17 Sep,

Usually the seal is an o ring. As a first step (they will have been unused for a few months) jiggle the pin up and down a few times. some silicone spray may help.
--
B Thumbs
Change lycos to yahoo to reply
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 17/09/2013 18:48, Davidm wrote:

I guess you could turn off the rad at the other end, freeze the pipe to the TRV and then drain just that rad. But I'd prob just drain the whole thing when convenient. Not a huge amount of effort.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Tue, 17 Sep 2013 18:48:32 +0100, Davidm wrote:

Donno about fixable but I shoul imagine you can get replacement inserts. Bit off they have started to leak after just four years. Get in touch with Drayton and see what they have to say.

http://www.toolstation.com/shop/Hand+Tools/Plumbers+Tools/Radiator+Val ve+Change+Kit/d10/sd210/p31768
http://tinyurl.com/m3jhbc4
They do work, I've used them when a TRV here got stuck and I wanted to take the insert out. Just make sure the system has no leaks and only open it at *one* point at *any* time. There might be a little spillage so still take precautions to protect carpets/decorations etc.
--
Cheers
Dave.
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Tue, 17 Sep 2013 20:37:36 +0100 (BST), "Dave Liquorice"

Ah yes, I've got a couple of these, I guess I have to plug both the feed and vent pipes at the tank. The "negative pressure" of the water won't damage anything in the boiler will it? I've heard tales of people who have seen hot water cylinders collapse when these plugs have been used on the hot water side of an open vented system and then opened a tap at the lowest point!
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Wed, 18 Sep 2013 10:31:45 +0100, Davidm wrote:

http://www.toolstation.com/shop/Hand+Tools/Plumbers+Tools/Radiator+Val

Yep. If air can't get in, water can't get out.

What "negative pressure"? Nothing is leaving the primary (or shouldn't...) if anything does it means some thing has got in some where. The system remains at it's static pressure determined by pure head.

Well I guess there is the "pull" from the weight of water in the pipe work below the cylinder. Which in a normal house with cylinder on first floor and taps on ground could be could be around 8' of head or 1/4 atmosphere.
--
Cheers
Dave.
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.