I recently removed my shower mixer valve which was faulty, the intention was to replace it with a new unit. When I checked the compression coupling sizes they were 22mm, this does not seem to be a standard size which from visits to the hardware stores seems to be 15mm. Does any one know of any models still using this size or do I need to amend the coupling on the fixed water piping.

Thanks

Although I don't know where your from, but standard sizes are 1/2" (5/8 OD) and 3/4" (7/8 OD). In the hardware stores, I've seen both dimensions used.

FWIW: If you go into a HVAC supply house and ask for a 7/8" elbow, it will be the 3/4" elbow that you bought at a plumbing store.

i recently removed my shower mixer valve which was faulty, the intention was to replace it with a new unit. when i checked the compression coupling sizes they were 22mm, this does not seem to be a standard size which from visits to the hardware stores seems to be 15mm. does any one know of any models still using this size or do I need to amend the coupling on the fixed water piping.

thanks

Most mixer valves are 15.88 MM wich figure out to 1/2" (Plumbing) or 5/8ths if your using AC as a size. Good luck. Tom

WYDGOP, are you from the United States? In the US, compression fittings come in 1/8" increments up to 1/2" nominal sizes (5/8" ID of the compression ring). 3/4" nominal is the next which is 7/8" OD pipe.

EPM

Compression fittings can be in 1/16" increments. Depends what he has.

We always stick to one size fittings + conversion fittings that convert to that size. This way we avoid hauling around entire warehouse full of various fittings.