Plumbing Questions? Ask a Plumber for Answers ASAP
usually what I have done with pipes that are seized is use some PB-Blaster or WD-40 and let the penetrating lubricant soak on the threads for a couple hours.
do you have room to get an adjustable(monkey) wrench on it?
be careful when you try using the wrench, make sure it has a good "bite" on the pipe before trying to loosen it.
also, you should put a "hold-back" wrench on the 90 in the wall if you have the room. otherwise you may damage the valve.
try the penetrating lube first and let me know how it goes.
Hi Lisa, if my info was useful, please click the green accept button.