I moved into my new house a couple of months ago and the previous owner didn't have time to connect the bathroom radiator. I thought I'd connect it myself since it's already setup to the point where I don't have empty the system (as far as I am aware) or anything like that. As you can see by the photo, I'm thinking all I need to do is just use the connector that screws into the radiator and join it with the existing old valve (using lashings of PTFE tape of course) that's already there. Unfortunately the radiator connecting part and nut is slightly bigger than the existing valve's thread. This applies to the lockshield side too. Do I have to replace the valve as well because won't this mean I now have to empty the system or is there an adjustor I can buy? It only seems a couple of mm smaller. I'm hoping it's just me being ignorant to all this and there is a simple and obvious solution! Thanks for any advice you can give me.
Youve got yourself the 3/4" lockshield valve whereas you need the 1/2" all you will need is the tail, olive and nut any plumbers merchant will have them in stock youll have to buy the full valve set though. Daft thing is Ive got a few floating aroubnd in the van
Thanks for your reply, the valve I bought is actually this one: http://www.screwfix.com/p/angled-radiator-valve-chrome-15mm-x/33920 The radiator connector part and nut is slightly too big for the existing valves so really not sure what's going on here. Actually just to clarify, when it says 15mm, I'm assuming it means just the size of the copper pipe connection with no relation to the fitting size between the radiator itself and the valve. If I went a bought a 10mm 1/2" valve would it make any difference? Thanks again.
No 10mm is the size of the pipe the valve is going onto. As is the 15mm, your right about the tail there are two sizes youn just happento have got the wrong one, unless you want to drain down and replace the whole lot. Havong said that it is possible to replace the valve by bunging the system and changing it but you need to know what your doing to do that method. Best advice i can give you is ignore screwfix B&Q Wickes etc go into a plumbers merchant and ask for a 15mm right angle lockshield valve with a 1/2 tail
Just to let you know, plumbing sizes make no sense whatsoever and imperial and metric are mixed freely.
Sorry but my ignorance seems to be getting the better of me as I'm still not sure what I need. The 10mm & 15mm issue is now clear though so thanks for that. The part that actually screws into the radiator itself is fine, it's 1/2" thread screws into the radiator without problems. It's the other end of this part that screws onto the existing valve that's the problem. The valve's thread is too small for the nut and other side of the radiator part to fit flush with the O ring. I did try to screw the 15mm nut on instead just to see if it would fit but the valve's thread seems to either be a different thread or about 16mm! It seems that radiator part will only fit the valve that it was sold with as it uses it's own thread & size for joining the two together whereas the outer ends are the standard sizes such as 1/2" etc. Something that started off so simple and quick now turns into emptying the system or freezing the pipe. Bum!
Dave the new valve that you bought is 3/4 inch x 15mm , what ppl are trying to tell you is you need a 1/2 inch x 15mm valve, if you get that it will provide you with the tail to screw into the rad, and the correct size but to fit ur existing valve.
Thanks but I'm trying to say that the one I have is 1/2" x 15mm. I even posted the link of the item I bought from Screwfix: http://www.screwfix.com/p/angled-radiator-valve-chrome-15mm-x/33920
Thanks but this is now driving me up the wall! I've just been to a plumber's merchant and showed him the valve. He has said what you said, it's got a 3/4" nut to attach the tail to the valve. He's sold me two tails that have 15mm nuts on. Unfortunately they don't fit either. The tails themselves fit inside but the thread on the old valves seems to be about 1mm larger or a different thread. It looks like the thread on these valves are of an old design so I don't know what size they actually are and if you can still get them. All I need now is just the nuts! ***UPDATE*** I think I know what the problem is (apart from me being green to all this!). As I have said, the 15mm nuts almost fit onto the old valves, in fact it feels as if the nuts were 16mm instead then they would fit. You can't buy 16mm nuts I know. However, 16mm is the equivalent to 5/8" so could mean that the old valves have imperial fittings? If so, then can I buy 5/8" compression nuts because I can't see any?
I think your problems have only just started - sorry! Trying to hang a rad on the wall to exactly line up the pipe heights and valve spacings is not easy. And if you get one side right the chances are that the other side will be out anyway. You are struggling to sort out the easy bit in my view, it gets harder the more you go on. My recommendation. Hang the radiator. Partly drain down, get rid of those old valves and fit the nice shiny ones. Build up the pipework to fit on the radiator. Add some inhibitor, refill, check for leaks, switch on, feet up and open a bottle of beer. Done!
Thanks. I'm sure I will run into more problems - it's fait accompli! The good thing (I'm sure it's officially a bad thing!) is that the pipes coming out the floorboards can bounce up and down a few inches so I don't have to be precise when or if I finally attach the radiator to them. Once attached I'll pull the board up and secure then to the beams. Regarding the draining, can you tell me the steps to do that apart from opening the valve in question and switching the combi off? Do I need to close off all the rads for example? I'm getting some conflicted opinions after doing some searches but that might be because they're referring to draining the whole system.
David, no disrespect, but get a plumber in, if your struggling to simply match up a rad valve, then I fear for your competence in fitting the radiator. It's a job that will take about an hour at the most.
Thanks for all your advice. You would (I did) think it was simple to find a compression nut that would fit the old valve but even after explaining it to a plumbing merchant and them selling me one that still didn't fit shows this particular valve isn't normal. I've now measured it properly, it is 5/8" and nobody sells them. The simplest part turned out to be the most awkward! Looks like I'm going to have to drain the system and stick new ones on. At least I can put a TRV on instead. Thanks again.
if its a combi boiler, you dont need to drain down , just remove system pressure.this can be done by opening the presure relief valve on the boiler ( another possible problem area) or use draincock to remove pressure, you can then break one joint and will only get a small amount of water whilst you do the job.sounds complicated but not for a plumber.
if you drain the system via the PRV you may find you will need to replace it because it wont stop leaking. stick to a drain off cock which will still probably leak but only while it is open
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