Radiator fitting mismatch

[Sprogginz]

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.

Untitled

• Sprogginz
• 19 Jan 2015
• 1

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.

 

[jackthom]

Is the new unused valve lying on the floor designed for 15mm pipework?

If so try out it's 15mm nut for size on the old valve, which may have been designed for a 15mm compression pipe tail along with an olive.

Screwfix do an adjustable length version which you may be able to use here.

http://www.screwfix.com/p/radiator-compression-valve-tail-15mm-pack-of-2/10954

 

[mfarrow]

Is the old radiator lying around? That will have the correct nut on it.

If not you'll need to drain the system down. Most compression joints these days use 1/2" BSP for the thread. Yours appears to be different for the new valve. Only the original will fit I'm afraid.

 

[Sprogginz]

Is the new unused valve lying on the floor designed for 15mm pipework?

If so try out it's 15mm nut for size on the old valve, which may have been designed for a 15mm compression pipe tail along with an olive.

Screwfix do an adjustable length version which you may be able to use here.

http://www.screwfix.com/p/radiator-compression-valve-tail-15mm-pack-of-2/10954[/QUOTE]

Thanks for your advice. The 15mm nut almost fits the valve. Not sure if it's because the thread is different or the nut needs to be 16mm instead!

I'm now assuming the two pieces in a valve set like the one I bought are not expected to be standard sizes where you can interchange with other valve sets.

It looks like I have to change the valve itself. Does this mean I have to empty the whole system?

Thanks again.

 

[Sprogginz]

Is the old radiator lying around? That will have the correct nut on it.

If not you'll need to drain the system down. Most compression joints these days use 1/2" BSP for the thread. Yours appears to be different for the new valve. Only the original will fit I'm afraid.

Thanks although this is what I was afraid of!

Never drained a system down so looks like I have to research more now... or mug a banker to pay for a plumber!

Thanks again.

 

[Madrab]

you only need to drain the system down to that point, if that's upstairs, it's a lot less to drain than if it's downstairs

 

[Sprogginz]

you only need to drain the system down to that point, if that's upstairs, it's a lot less to drain than if it's downstairs

Thanks. I didn't know that was possible but see the logic now. Just done some research on that but there seems to be conflicts on how to do that.

Do I simply shut off all the valves on the upstairs radiators, then simply drain what comes out the valve in question?

Should I switch off the combi as you would if doing a complete drain?

Thanks again.

 

[bazdaman]

If its a combi open the old valve into a bucket you may get half a bucket, when pressure has gone swap the valve, no need to drain the system to chamge a rad valve

 

[Madrab]

you only need to drain the system down to that point, if that's upstairs, it's a lot less to drain than if it's downstairs

Oh, apologies, was running back and forth during the last post, forgot to add - If it's not a combi boiler (a sealed system), then it may be a gravity fed circuit with a system boiler. That will have a feed and expansion tank in the loft, top of the house. The feed from that will need plugged up to stop it filling the system as you drain.

 

[bazdaman]

you only need to drain the system down to that point, if that's upstairs, it's a lot less to drain than if it's downstairs

Oh, apologies, was running back and forth during the last post, forgot to add - If it's not a combi boiler (a sealed system), then it may be a gravity fed circuit with a system boiler. That will have a feed and expansion tank in the loft, top of the house. The feed from that will need plugged up to stop it filling the system as you drain.

OP said it was a combi

 

[gigz]

Take a picture down to the merchant, he'll give you the tail that matches the existing valve if you don't want to drain down. Or even your local scrapyard.

 

[slapper]

Don't forget when waters pizzing thru the ceiling to MUG that Banker to pay for the Plumber

 

[Madrab]

OP said it was a combi

Doh, forgot about the later post, I need to stop posting when I should be in me bed

 

[Sprogginz]

Thanks for all your replies I really appreciate it.

Before I go off and flood my house, I have just one stab in the dark that might solve the problem if anyone knows.

I now have tails that fit into the old valves, these tails come with 15mm nuts that screw onto the valves. I can see this seems to be the standard size.

The 15mm nuts almost screw onto the valves but not quite. In fact it feels as if it needs to be 16mm then it would fit. You can't buy 16mm nuts can you?

However, 16mm is the equivalent to 5/8" so could it mean the old valves have imperial fittings in which case is it possible to buy 5/8" compression nuts because I can't see any at the moment. Or is this theory just pants?

Thanks again.