Clarification question - remove problematic Zurn Wilkins 975XL backflow prevention valve

I have to agree with you, after reading the package at the store for the

The package says it's for protection from corrosion.

Of course, it did nothing for the corrosion on the *inside*!

The 1-inch valve is brass. The 1-inch pipes above ground to each side of the valve are all galvanized. Below ground, a foot or so away, a used the 2-inch red-handled PVC shutoff. Then the pipes come back above ground at 2-inch galvanized into the pressure pump equipment in the pump house.

This picture shows the water pipe to the right going from the pump house into the ground, and then one of two valves underground (one for the house, the other for the irrigation system).

I think it's odd they go from steel to pvc to steel, but they do. The PVC seems to be only underground though.

I have to agree with you on that.

After removing the sticky tape, I noticed that it was still *very* sticky even after a few decades out in the open, but at the hardware store, the package for the 10mil pipe tape said it's to protect the pipes from corrosion.

Since the pipes were galvanized into the ground, I guess they wrapped from the ground up, and just didn't bother stopping at the surface.

I never understood how "insulation" works on a water pipe, where the water in the pipe is the same temperature as ambient.

There's no delta in temperature between the inside and outside; so what's there to insulate?

I took your advice, and didn't trust my measurements.

In fact, I am glad I did the dry fit at the hardware store, because the pipe nipple that worked was an inch shorter than I had measured!

I did learn a bit, e.g., I put the teflon pipe dope on the threads but I didn't bother with the black 10-mil tape, after asking at the hardware store what it's for.

I also made some unexpected mistakes.

For example, I never could get the downstream pipe joint to open because the entire assembly kept turning underground instead!

that is not all that much corrosion.

I always use 2 pipe wrenches when working pipes. Not doing so is why novices cause more leaks than they fix.

Oren posted for all of us...

Don't forget to take your 500 mg dose of Fukitol. I'm up to 1000 mg.

In fact, in further hindsight, I could have cracked one pipe-union nut first, and then, before disconnecting it, cracked the other.

Then I could have done it with the one pipe wrench that I used. (I have more pipe wrenches - I just didn't lug them up the hill.)

What, are you saying there's a way out of using 2 wrenches? Then you're not paying attention. Always use 2 pipe wrenches, even on unions. Believe it or not, an over-tightened or frozen union nut can resist turning enough to where fittings on either side both tighten and loosen. And not necessarily the first fitting from the union. It's happened to me more than once, though it didn't matter because I was junking the old pipe. This advice doesn't matter much, since hardly any DIYer encounters steel pipe anymore.

Um... that's what I "was" saying. Until I read the rest of the post below.

I apologize. I had not realized you would have used two pipe wrenches even if there were only a single union. Now I understand. I had not understood that before. My mistake.

I see. It does make sense. Thank you for having the patience to clarify.

That makes sense.

Yeah. Disassembly to take stuff apart that will never go back together is always easier than any other job!

I think most of my house is copper, but the outside seems to be galvanized, and my sister's house, which I also maintain, is all galvanized from the sixties. Those pipes have nodules of stuff inside whenever I replace them.