what is a S union for

[bobby_la_mesma]

Dear All

I have purchased a Grohtherm 3000 thermostatic shower mixing valve. I thought this is going to be easy. Pull two 1/2inch pipes through the wall and join the the value.

In the box they have sent me two types of connection to the valve which has now confused me.

1 box containing part number 18862 045 (2x 90 deg 3/4 to 1/2 inch compression joints)
1 box containing part number 12058 045 (2x S union with two sealing washers)

http://www.grohe.co.uk/lib/1/tpi/1342885.pdf

My feed is on the other side of the wall so I did plan to route through two 1/2 inch pipes and connect onto the valve. However there is an S union in the box which I have never seen before. The S union has a far smaller internal diameter than the alternate (90 deg 3/4 to 1/2 inch compression) fitting.

I have a shower pump but don't know which connection to use. Also, if I fit the S union, is it just a compression joint to made off on the 1/2 inch end? The pack did not contain a compression nut or olive. And to add to the confusion the web page above which illustrates the part number 12058 045 has got the washers, which comes with the pack crossed out!

If you have any ideas I would be grateful. I'll be calling tech support in the morning otherwise.

Thanks Rob

 

[doitall]

It allows you to adjust the bar so it's level.

 

[Hugh Jaleak]

FWIW when I fitted something similar I used the 2 'S' unions, these had male iron threads, compression joints weren't suitable. (Hence not supplying nuts and olives.) I was fitting it to a false wall so life was easier as I could line the 'S' unions up with shower level before tightening the MI fittings onto the supplies.