I would like to replace the old style shut off valve with the new 1/4 turn angle valve. My question is can I just unscrew the red part and screw in a new 1/4 turn one to the blue part so I don't have to make cuts to the pex pipe?
How to replace sink shut off valve
shutoffsinkvalve
Related Solutions
You need to find the main shut off valve in the road, side walk or somewhere on or near your property. They are usually placed in mini manholes with easy access:
But if you're unlucky you will need to get some building plans and try to find where on the plans the supply pipe runs and find the valve at the connection point to the main supply. In most cases it will be near the connection point of the main supply:
but if its not, or if you struggle to close it call your council to help you. You don't want to break that!
NB
It is easy to snap these valves- if its rusted badly apply (known as WD-40, LN-40, HT-40) spray oil based rust release (spray leave an hour try again.. repeat a few times), TAP the valve with a hammer (!TAP!, do not whack it, to help release the valve. Also, usually opening the valve slightly helps to release it then try to close it.
That's most likely a copper pipe covered in solder. You can try scraping the solder off to see if you get down to some copper to verify. A copper pipe cutter is cheap and easy to use:
Get this onto the pipe a close to the valve as you can, tighten the screw until it's snug, and spin it around the pipe making sure to keep spinning on the same location (you're making a cut, not treading the pipe or making a spiral). After every few turns, tighten the screw a little more and eventually the pipe will break off. Clean the pipe with some emery paper, and install a new compression style valve (this only requires a few wrenches (crescent or fixed, not a pipe wrench or pliers if you want to avoid teeth marks). If you removed too much of the pipe, you may need to replace the escutcheon with a flatter style.
Best Answer
This doesn't appear to be PEX pipe but a 1/2' or 3/8" compression inlet. Remove the valve by unscrewing the red part and take it to your plumbing supply store so they can attempt to match the compression face and threads. If the compression sleeve and nut come off the pipe easily, take them with you too. Your valve stem is PVC so I'm curious as to why you want to replace the valve.