Fitting radiator TRV's 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. He
noted that the TRV's the instaler had fitted were one-directional, said
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. All
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 the
copper pipes seem to be attatched to what I presumed was the old brass
o-rings! They rotate, but would probably need cut off or an awful lot more force than I would expect. Unless I can get these off, the old fitting nut wont come off, and I cannot fit the new parts anyway. Any help would be gratefully appreciated. Thank you in advance.

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

http://i29.photobucket.com/albums/c...jung/NEWTRV.jpg

http://i29.photobucket.com/albums/c...XPLODEDVIEW.jpg

http://i29.photobucket.com/albums/c...jung/OLDTRV.jpg

http://i29.photobucket.com/albums/c...ttingOnPipe.jpg

 

[Slugbabydotcom]

TRV's only need changing if they are causing a problem. Cheaper to turn them round or fit them to the correct end. This knocking is audible so if you cant hear it and the rads work there should be no need to change them.

All
that is in the boxes are a two-way valve, two brass o-rings, two nuts
and the sliding tail.

Plus the thermostat head and a cap of some sort to protect the valve body when decorating / operate the valve as a normal wheelhead valve etc

Threaded end of tail goes into the rad; normally with some ptfe tape on it, unless it is already coated with PTFE of course. I have just had a lookat the mistral valve and it appears that this is the self sealing bit so you wont need any PTFE as the seal is provided by an O ring on the fitting.
Then the nut goes on followed by the ring
Then the valve body
Then the other nut and ring go onto the pipe.
The head is set to it's highest setting then fitted to the valve body after the nuts have been tightened

When you tighten the nuts up nothing should slide anywhere as they compress the ring around the pipe/ tail

The other bits you saw on the ebay site were probably reducers for 10 or 8 mm pipes

 

[don72]

TRV's only need changing if they are causing a problem. Cheaper to turn them round or fit them to the correct end. This knocking is audible so if you cant hear it and the rads work there should be no need to change them.

All
that is in the boxes are a two-way valve, two brass o-rings, two nuts
and the sliding tail.

Plus the thermostat head and a cap of some sort to protect the valve body when decorating / operate the valve as a normal wheelhead valve etc

Threaded end of tail goes into the rad; normally with some ptfe tape on it, unless it is already coated with PTFE of course. I have just had a lookat the mistral valve and it appears that this is the self sealing bit so you wont need any PTFE as the seal is provided by an O ring on the fitting.
Then the nut goes on followed by the ring
Then the valve body
Then the other nut and ring go onto the pipe.
The head is set to it's highest setting then fitted to the valve body after the nuts have been tightened

When you tighten the nuts up nothing should slide anywhere as they compress the ring around the pipe/ tail

The other bits you saw on the ebay site were probably reducers for 10 or 8 mm pipes

They were banging severely and often, causing the Bar-Gauge on the boiler to go wild. So the o-ring seals the tail after it is tightened? I was worried about this as the ones I've seen on ebay all seem to come with a little brass part. Can you confirm that it's a reducer? Heres a pic of how it's shown on ebay, and a link to the auction I found it on.
http://cgi.ebay.co.uk/Yorkshire-Mis...oryZ3191QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

I take it "olive" is another word for the o-rings the o-rings.

Thanks for your help here! As you can tell this is my first ever diy plumbing attempt and I'm pretty nervous. I dont want to cock it up.

 

[Slugbabydotcom]

Nice one for posting the pics

So the o-ring seals the tail after it is tightened?

Yes When you tighten the nuts they compress the brass rings around the pipe. look at the contacting parts of the nuts and fitting you will see that they are chamfered to squeeze the ring aound the pipe / tail and make the seal

I cant see a rubber O ring on the threaded part of the tail so you wont do any harm by giving it a wrapping of PTFE tape even if there is one present


EDIT : If there is no rubber O ring you will need to use PTFE tape.
Olives and brass rings are the same thing.
O rings are 'rubber'

 

[don72]

Brilliant. I did at least buy some PTFE tape, so as soon as I manage to get the old olives off I can get this job done. Youre a scholar and a gentleman. That was top-class help sir!

edit:
I'm having trouble fitting the valves, even if everything was tightened the bottom pipe is too far from the valve to slot in. Is there a way to do this without removing the rads from the walls and bending the pipe somehow? Heres a pic showing the closest the connector can get to the pipe. There's less than 3 inches of copper pipe to work with from the join below (that feeds to the rad on the other side of the wall).

Could it be I should have been sold this model instead? It looks more like the ones I had fitted and took into PlumBase to show them.

edit2: that brass part that I was worried about might be a "straight male connector" from what I can see on Yorkshire Fittings site.

http://www.yorkshirefittings.co.uk/fittings.cfm?brand=01&defsub=01[/img]

 

[Roddders]

You have fitted the TRV on the wrong way round! Undo the compression joint in order to remove the TRV head. TRV head should be vertical not pointing out to the right as indicated on your photo. You may need to remove old PTFE and put on some more before refitting it.

Before you connect the TRV head if you line it up along side as though you have tightened up the compression joint you can then see if the tail pipe is too long. (Looking at your picture it may need a small amount taking off. Make it to fit as snuggly as possible. I tend to put a turn on the compression to fit the TRV loosely to the radiator then rotate the valve in order to slot the tail pipe into the base of the TRV, remeber to put compression nut on tail end first followed by olive then, do the above. Once in position, tighten compression on TRV nearest radiator tight then tighten up compression on tail end of TRV.

All the best with it.

 

[don72]

You have fitted the TRV on the wrong way round! Undo the compression joint in order to remove the TRV head. TRV head should be vertical not pointing out to the right as indicated on your photo. You may need to remove old PTFE and put on some more before refitting it.

Before you connect the TRV head if you line it up along side as though you have tightened up the compression joint you can then see if the tail pipe is too long. (Looking at your picture it may need a small amount taking off. Make it to fit as snuggly as possible. I tend to put a turn on the compression to fit the TRV loosely to the radiator then rotate the valve in order to slot the tail pipe into the base of the TRV, remeber to put compression nut on tail end first followed by olive then, do the above. Once in position, tighten compression on TRV nearest radiator tight then tighten up compression on tail end of TRV.

All the best with it.

Thanks. The tails definatlely need to loose at least 5mill. It's possible I can get them machined. I don't know if an angle grinder would be up to the job of cutting through the metal and if it did it would invalidate the warranty at the least. I think I'm going to just try to get valves that fit.

I thought it was more effective mounted that way, but it looks like it might only be if mounted on the return end.

 

[Slugbabydotcom]

A valve fitted head out works better as it wont pick up as much heat from the rad which is likely to switch it off early. - Not though you would notice it as you find your own setting for the TRV by asking yourself if the room is warm enough and adjusting accordingly.
Head up looks better, is more conventional in appearance and mainly is less likely to be knocked about.
I would either jiggle the rad up 2.5mm along the bracket sharing the strain at both ends of the rad and / or fit this valve 'head up' then if you loosen the nut off slightly it is often the case that you can gently tap the valve further towards the rad. Its to do with the space that was occupied by the nut when you started tightening.
If that doesnt work then you could use an angle grinder or better still a hacksaw to take the 5mil off. Take it easy with the grinder. It is chrome plated brass and much softer than steel, also if you slip you could damage the pipe.
A much simpler solution may be to turn the existing valves round whether they are 'head up' or 'head out' so that the arrow on them is the same as the direction of water flow through the radiator.

 

[don72]

Thanks again slugbaby and everyone who took the time to reply. I believe the actual tail is iron going by the mistral pdf. I've had a change of tack now anyway, and will only be replacing the bedroom TRV. I'm installing standard valves on the living area rads and fitting a room stat. From what I've been reading, and I've been reading every plumbing site I can find, it would be an all-round better option, saving energy and wear and tear on the boiler.
By the time I hired a coring drill to go through the six-inch blockwork I reckon I'd be as well to pay for a cheapish wireless unit. Going to plumbase tomorrow morning so I'll hopefully get this finished over the weekend. My electric heater must be costing a fortune by now.

 

[PEDANTICVINDICTIVEMAN]

Dont forget to get the installer to come back and fit the room stat for free, it's not an "optional" extra but a "REGULATION", he will of course have priced for it in his original quotation, just like everyone else will have done who quoted, he must have "forgot" to fit it, it wants to go in the room which has not got a t/valve on the radiator, normally the hallway, oh yes and you will need to make sure he ticks the box in the "benchmark" logbook saying he has fitted it, then when your Gas Certificate comes in the post from when he registers the installation, it will all be hunky dory, dont forget it freeeeeee internet providings.

 

[imroberts]

Was it a regulation back in 2006?