15 mm fittings wont connect to old radiator valve, what should I do?

[Gary111]

Hi, I am trying to fit a new radiator but the 15mm compression fittings are not going on the old valve thread.

I'm not sure what to do, I can try to get the old fittings out of the radiator but I can't see that being easy.
Maybe I can just cut the nuts off and use them with new olives?

I also need a bit more length on the pipe as the new radiator is slightly narrower.

 

[Gary111]

 

[opps]

I am not a plumber.. I think you can use an olive puller and then replace the olive with a new one. That said, in my current home, some of the valves were tightened so much that it deformed the 15mm pipe, and I had to solder in new 15mm pipe work.

If your's haven't been over tightened, use an adjustable spanner, whack the bottom nut upwards until the olive moves. Might be prudent to wrap the olive with PTFE though.

 

[Wayners]

Use extender if not long enough.
Valves come with rad inserts that match up.
Not sure which you need

 

[terryplumb]

Is the problem that the new silver nut doesn't screw onto the thread of the old valve because they are different thread patterns ?
Pictures can be deceiving ,but the thread on your old valve doesn't appear to be the widely used 1/2 inch BSP ??

 

[opps]

Sorry, my bad, I didn't read read your post properly. If the rad is smaller width wise, as @Wayners said, use extension tails

In my addled brain, I read your post as the new valve would not pull up the olive enough to let you fit the new rad valves.

 

[Wayners]

Fit new valve with matching insert. They come together.
You have sealed system?

 

[Gary111]

Is the problem that the new silver nut doesn't screw onto the thread of the old valve because they are different thread patterns ?
Pictures can be deceiving ,but the thread on your old valve doesn't appear to be the widely used 1/2 inch BSP ??

Hi Terry, yes they must be different thread patterns, the house was built in the 70s if that's any help?

 

[Gary111]

 

[terryplumb]

Just use the nut that connected to the valve originally.

 

[terryplumb]

That valve looks like a Prestex make, they used different threads to most other brands.

 

[opps]

That valve looks like a Prestex make, they used different threads to most other brands.

Fair play, but why?

 

[terryplumb]

There was nothing to stop them using whatever thread patterns they chose to. Not every country in the world uses the same thread patterns as we do on plumbing fittings,maybe Prestex had larger markets in other countries and saw no reason to deviate in their manufacturing process.Anyones guess what the reason was really.

 

[Gary111]

That valve looks like a Prestex make, they used different threads to most other brands.

Thanks for your help Terry, you are spot on there!