What Size Union for CADE 900 S2?

[JoeinLA]

Hello, I'm hoping someone can tell me, or perhaps even provide a link to, a union valve / ball valve to buy to connect to the return line of a CADE 900 S2 (though I understand that all the CADE S2 systems use the same plumbing). I asked AlgaeBarn, but the only could send me the following info below.

I looked up DN20 on Amazon and ordered this, but it's just a bit too large to connect to the union in the CADE's return line:

TOMEX 3/4" Inch（DN20) PVC True Union Ball Valve with Full Port, NPT F1970, EPDM O-Rings and Reversible PTFE Seats, Rated at 150 PSIat 5℃/max55℃ , Gray and Red​

Any help would be greatly appreciated. Thanks.

 

[lapin]

I looked up DN20 on Amazon and ordered this, but it's just a bit too large to connect to the union in the CADE's return line:

I dont think you can screw the 2 together unless its the same manufacture and even then they could be different
Not all unions have the same threads that holds the 2 parts together.
They will be the same inside lets say 3/4 ID in one brand will be 3/4 ID in another. So the pipe fit in each.

 

[JoeinLA]

So does that mean I’d have to cut off the current union and weld a new one as a replacement? Not sure I want to monkey around with it that much.

i suppose i could just use a hose to attach another union/ball valve further down the line.

surprising that these things aren’t more standardized

 

[lapin]

you got it
When it comes to unions i always buy 1 or 2 extra. If I ever need to replace pipe thats cemented, I can use the part of the union I need.