Options for fitting radiators with straight valves

Discussion in 'Plumbers' Talk' started by carl2013, Nov 17, 2013.

  1. carl2013

    carl2013 New Member

    My wife and I are doing up a house and we're finally around to fitting the radiators. I put pipes in place to come out of the walls before the plasterboard and skimming went on but made some wrong assumptions about how the valves are fitted. I thought it would look better if the pipes came out of the wall instead of the floor so I made them come out either side of the radiators level with the valves. The radiator valves are straight (instead of angled) because I was planning on adding an elbow after the pipe exits the wall and then running them straight into the valve and radiator horizontally. See the diagram attached.

    I've connected them all with nice chrome compression elbows but it leaks, maybe because the pipes aren't aligned quite right and there's a bit of tension on them. I could solder an elbow with the radiator in place, less places for it to leak, but it'll be almost impossible to get the radiator off later without cutting the pipes. Also some of the radiators have plastic pipe just out of reach inside the wall so I can't solder the little bit of copper that's sticking out. I've already had to solder a few extension bits onto other radiators because I didn't leave enough pipe sticking out of the wall. This is all 15mm pipe.

    We've considered using push-fit elbows like Conex Cuprofit but I suspect they might damage the pipe after removal and they're just as likely to leak as the compression fittings. Or we could use 10mm copper or plastic pipe with a reducer inside the valve and simply bend this from the wall to the radiator. We would still need to reduce the 15mm pipe from the wall to 10mm. Speedfit reducers are big and ugly, Copper pushfit look a bit better but won't take plastic pipe.

    Ideally, I would have got angled TRVs and brought the pipes out directly below with a bit more movement in them, or I would have used 10mm pipe coming out in the middle of the radiator, or I would cut out the walls and relocate the pipes. Unfortunately, time and budget don't allow this at the moment.

    I'll know better next time but can anyone suggest a good looking and reasonably leak-proof solution for hooking up our radiators to my awkwardly positioned pipes?

    Attached Files:

  2. Soldered joints will indeed make the rads hard to remove, although the joint betwixt the rad valve and the bit your first screw into the actual rad doesn't require that much movement before they can be slipped apart. Mind you, if you undo that joint, then the rad's contents will be dumped...

    Which joint is leaking? Even if there is a bit of sideways strain, it should still be quite possible to make a compression joint water-tight; olives are quite forgiving. Did you add a smear of joint sealer on he pipe and around the olive - and on the thread, as it makes fine lubricant, and tightening it all up is sooo much easier?

    Cupro-fit (copper push-fits) will fit on plastic pipe, so that's an option. Also they allow rotation, which could help come removal.

    You can also get rad leg extenders - y'know the bit of the valve you screw into the rad itself? You can get longer ones of these.

    In what way do you need to adjust the pipe or rad? Up a teeny bit? Sideways a bit?

    Push-fit fittings shouldn't damage the actual pipe as long as they are removed carefully using the right tool - one that presses in the end sleeve to disengage the grab ring. They do score the pipe surface, but only near the end of the pipe and before it reaches the part where the sealing O ring does its job. I think I'd rather use compression, tho', in this situation.

    Redo your elbows but add a smear of joint compound - a thin smear on the actual pipe, slip on the olive and add another smear over this, and also a smear on the male fitting thread.

    See if that helps.
  3. carl2013

    carl2013 New Member

    Thanks for your reply. It's good to hear another opinion on this (despite your user name :p). It gives me hope that there might be a solution. I'll reply roughly in order to your suggestions.

    Several joints were leaking on several of the radiators. One place was because the tail wasn't far enough into the valve compression fitting so the olive collapsed over the edge of the tail, but everywhere else had a decent length of pipe inside the fitting as far as I could tell. There were small leaks where the tails fit into the rads as well as round some of the elbows. First time I hoped that the compression fittings would just work but I did use PTFE around the tails, wrapped clockwise. Second time I took them all off and put joint compound (Hawk White) on top of the olives and the male threads of the valves and elbows. Similar leaks, not everywhere but several different locations. I've read a few places that it's not a good idea to put compound under the olive as it can slip, but everyone seems to have different ideas about how to seal things: nothing on a compression joint, hemp + boss white, non-setting compound, PTFE, gas PTFE, 3 wraps, 20 wraps, PTFE around the olive, compound under the olive, no compound under the olive... :rolleyes:

    I've now acquired some gas PTFE tape which I hope will help, at least on the tails. I've carefully cleaned the threaded hole in the rad and the tail with a wire brush.

    I may have overtightened some of the joints the first time round and now the olives are impossible to remove. In a few cases, I can't pull the outer ring back far enough to get a grip on the olive with pliers or a hacksaw because a soldered joint is in the way.

    You're right about Cuprofit being ok on plastic (checked the manufacturers docs, just need a different type of insert), but I'm sure I saw somewhere that it's for copper only. Maybe that was Wickes own brand or Tectite or other.

    Good idea about the rad tail extenders, although I've only found the telescopic ones not plain fixed length ones. It should help in the one spot where the pipe is a tad short but I can't resolder because of the plastic fitting nearby. Hopefully these don't leak either.

    Some of the pipes don't come out quite level with the rad, so the connection has to slant up or down by half a centimetre or so over the few inches between the pipe exiting the wall and the rad. I'm going to cut out some space around the pipe where the plasterer has filled with skim. This might give me a bit more movement, but the pipes are also held in place by plasterboard adhesive and a few brackets inside the wall and there's not much I can do about that. I've pushed and pulled on the pipes to try to get a better alignment but it's not quite right in places.

    I think I'll try refitting the tails with some more wraps of gas PTFE tape. On the radiator with the short pipe I'll use the tail extender. Everywhere I'll try to use the chrome elbows again (they look nicer and we can finish the pipes with chrome covers) being careful to put compound on the olive and on the male thread.

    Is there a particular way to test a system for leaks? It's pretty stressful running around 5 or 6 rads with paint trays trying to save our new carpets. Previously, I closed the TRV and lockshield and then opened them on one radiator and opened the bleed valve before moving on to the next radiator, but I wonder if the compressed air somehow blows the seal in the compression joints. Maybe I'd be better off leaving the valves open when I turn the water back on...
  4. Last bit first - the compressed air in the system ain't going to 'blow' your fittings any more than water itself will. As won't turning the rad valves on before or after refilling. If your joints are going to leak, they are going to leak. If they ain't, they ain't :).

    The pipes wot come through the wall slightly too high or low; use a chisel or similar to cut a slice of wallboard from whatever side of the pipe you need. Just go for it (without cutting into the pipe...). Once you shift the pipe, slip a decorative collar over the pipe and glue it to the wall. Jobbie jobbed.

    The pipe that's too short - fair dues that that one didn't seal :(

    As for the others, it seems a bit surprising. You are right - pros will go on and on about the 'right' method of preparing and sealing pipes, so my thoughts above were just that - mine.

    But they work for me.

    In fact, I've recently used the same stuff you mentioned - Fernox Hawk White. Sticky goooey stuff, but makes the threads tighten smoothly, and has worked for me just fine.

    I've used PTFE tape in the past, but wouldn't rely on it now. It's also my personal choice to add a smear on the pipe itself first - by the time the olive is slipped on, all that's under the olive is a very thin coating. And it's pretty obvious that 99% of that will be squeezed out during the tightening process. So, that leaves just a trace under there - filling any scratches or gaps that are there. I'm more generous with the amount wiped over the olive, and ditto on the threads.

    To get that stuck olive off, try gently using a a plumber's 'waterpump' wrench (such as http://www.screwfix.com/p/fatmax-groove-joint-pliers-8/33119 ). Open it sos' it spans the loose nut fitting behind the olive and also reaches the end of the exposed pipe. Put something over the pipe end to protect it ( a coin?) and gently try squeezing the end nut (and olice) down towards the pipe end. You'll need to alternate the sides you are pulling on, so's the olive isn't being drawn sideways.

    Might work.

    Use the hawk white (ok, along with PTFE is you want) on the rad tails. But just the Hawk on all other fittings. Nip up the fittings but don't over-tighten.
  5. kiaora

    kiaora Guest

    What's the height of the rad? I always fit rads 8" from the floor, can you. Raise the rad and pipe it from below with angled valves?
  6. carl2013

    carl2013 New Member

    [Huh. Why didn't this get posted yesterday? I'm sure I hit the post button...]

    Thanks again. I'll give the compression fittings another go tonight.

    I could also get an olive puller which looks really shiny and lots of fun but at £25 I'll try using the wrench first.
  7. carl2013

    carl2013 New Member

    Hi Peter,

    Good suggestion but I don't think it'll work for me. The pipes, valves, and bottom of the radiators are currently 9 inches from the floor (actually it was a mistake because I misheard the height of the skirting boards but it looks OK). Putting them any higher would be too high I think. Also I'd have to move the pipes inwards by a couple of inches each to come up directly under the valves instead of further out, so either I'd have to cut out some more wall or I'd have an extra really odd looking elbow to get the pipe into the valve. I'd rather not have to buy new valves for 5 radiators or move the pipes. Next time: I'll get angled valves and I'll bring the pipes up into the radiator vertically instead of across horizontally.

    This all started because I really wanted to avoid pipes coming out of the floor. I assumed the alternative was to have them coming out of the wall and across and never thought that they should really come out and up.

    I've refitted all the compression elbows and used plenty of Fermox Hawk White paste. I polished the pipes with steel wool too and made sure they were nice and dry. I've been careful not to overtighten so this time each connection is finger tight plus one turn max. I'm afraid some damage may already have been done to the pipes earlier because I did need the olive puller to take almost all of them apart and some of the pipes had the imprint of the olive (slightly smaller diameter). I'll test it this evening. If it still leaks I may have to cut all my walls open and get new valves :-( Not sure the plumber will be happy if he comes tomorrow to fit the boiler and I tell him that the rads aren't ready.

    -- Carl
  8. carl2013

    carl2013 New Member

    It seems to have worked. I followed SC's suggestion of reusing the compression fittings with new olives and some Hawk White jointing compound under and around the olives as well as on the male threads. I only tightened hand tight plus one turn max, tightening the spanner with a single finger. I also cut out a bit more space around where the pipes come out of the wall so they can adjust more easily. When I turned the water on, a couple of places were spraying but I was easily able to tighten up those. A few radiator tails were leaking too but I was able to tighten most of those.

    Two problematic places. One compression on a radiator tail was very difficult to get tight and kept dripping. I couldn't get a good enough grip on the valve to stop it spinning, had to remove the TRV part as I was worried I'd crack it. Ended up scratching the chrome on the valve but I think the leak stopped. The other place I decided to replace the pipe coming out of the wall which had been crimped due to overtightening. I missed the sweet spot when soldering and the solder didn't flow. Tried to reheat and remove the new piece but the next bit came with it. Had to cut out even more plasterboard and foam to avoid burning down the house when trying again. Worked OK in the end.

    The olive puller was very handy. I had overtightened far too much on my first attempt but even though some of the pipes were crimped (is that the word?) the joints seem to be ok. I need a figure out the trick of holding the TRV, lockshield, or elbow for those times when I need to tighten a bit more than usual. I've been using an adjustable spanner on the nut while using adjustable pliers to hold the body of the valve with a folded rag which tends to slip or still scratch the finish.

    Plumber is installing the boiler today. Hopefully he's able to commission the c/h system without any issues and we'll have some heat tomorrow.

    Thanks for all the advice and a nudge to give the compression fittings another try.
  9. Well done with persevering - sometimes you spend ages working around an inaccessible part hoping it'll work without causing damage to the surrounding area, and then you have to go 'sodit' - and hack away. Worth it in the end.

    Holding the valve body firmly is a problem. I don;t know what pros do, but I tend to use a Mole-wrench for that; remove the TRV head (for the reason you said!), and that'll give access for the grips to clamp the sides of the valve which is slightly flat. A good bit of card or cloth to act as a protection for the chrome, and then clamp down hard so it doesn't shift.

    Clamping the Mole grip doesn't cause any damage - provided the valve doesn't move. So, clamp firmly.

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