5/8 male thread on expansion vessel?

[jpowell79]

Was just about to fit an external expansion vessel yesterday.

https://www.plumbnation.co.uk/boiler-spares/product/worcester-87161425040-expansion-vessel-10l/

I just assumed (without actually looking!) that the thread on the E.V. would be 3/4" so I purchased a 3/4" female to 15mm compression fitting but it's too big.

Having measured across the EV. male thread it appears to be 5/8, so I guess I need a 5/8 female to to 15mm compression.... but I can't find any of these anywhere! I'm starting to think they don't exist !

This is such a well known EV though that I'm surprised it seems to be a non-standard thread? Any ideas what's going on here???

 

[gasmanstu72]

that's not an external pressure vessel, that's one for a worcester 350 if 'im not mistaken

this is an external one with a 3/4 thread: http://www.plumbcenter.co.uk/product/altecnic-expansion-vessel-12-ltr/

 

[muggles]

Was just about to fit an external expansion vessel yesterday.

https://www.plumbnation.co.uk/boiler-spares/product/worcester-87161425040-expansion-vessel-10l/

I just assumed (without actually looking!) that the thread on the E.V. would be 3/4" so I purchased a 3/4" female to 15mm compression fitting but it's too big.

Having measured across the EV. male thread it appears to be 5/8, so I guess I need a 5/8 female to to 15mm compression.... but I can't find any of these anywhere! I'm starting to think they don't exist !

This is such a well known EV though that I'm surprised it seems to be a non-standard thread? Any ideas what's going on here???

I'm afraid starting a new thread and calling it an external vessel, doesn't make it an external vessel. It's not an external one, it's an internal one and the thread will match the thread inside the boiler it is designed to fit. There's no such thing as a 5/8 to 15mm, you'll need something like this and you can then put a 3/4 × 15 onto that.

 

[jpowell79]

Turns out it was a 3/8 not a 5/8.... doh!!

Got one of these from Stevenson

https://www.stevensonplumbing.co.uk/15mm-x-3-8-inch-compression-female-adaptor.html

All sorted...


now on to the next thing.... rads cold at the bottom!