Replacing Main Shut Off Valve

[casman]

The water company has already shut off the water. There is copper coming up from the floor, to a brass 90, then the shut off. Replacing with ball valve. I will soon attempt to remove the old valve. I have already given it a shot lightly and it may be frozen. I'm thinking about heating up the threaded area with a torch to loosen it???, there's gunk on the threads and obviously I don't want to snap the pipe off. I am planning to block the pipe against the wall with a 2 x 4 so that when I attempt to remove it doesn't twist etc, or there is a spot on the 90 elbow for a double wrench setup, is there a preferred way to do this carefully? For the new ball valve gizmo is it correct to use teflon tape on the threads? Thanks

[Terry]

Heating the threaded portion lightly with a torch will expand the female portion of the valve making it easier to remove using two wrenches.
You will want to hold the fitting on the copper while doing this.


I would use a paste thread sealant.
I've seen too many problems caused by Teflon tape.

[Deb]

Make sure that you understand this "2 wrench thing", a 2x4 against the wall will not keep the pipe from twisting. You need 1 wrench on the copper male adapter, or brass adapter, or brass street 90 or nipple (not sure how the valve and the brass 90 are connected) to hold it stationary while you use the second wrench to unscrew the old valve. If you do not do this, you will most likely damage the existing piping. Where is the piping disconnected on the other side of the valve? If you need to solder anyway, you may just want to cut the old valve out and solder a new sweat ball valve in. I've always sort of thought that soldering a male adapter on a copper line to attach an IPS fitting just made 2 connections when 1 would have sufficied.
Deb
The Pipewench