Should I be concerned about corrosion? (new connection to old pipe)

[Arnold]

I'm a handy DIYer working on replacing my old pipes with PEX. I feel confident with my research, design, and plan but I've had to replace a couple of sections of pipe in the past few years due to corrosion (hired a professional for those because it was an emergency) and I am concerned with making the final connection to the main when I actually get around to doing this. Image attached.

Optimally I would like to disconnect below the main shutoff valve, at the first elbow coming into the foundation, so I can replace the valve as I connect the new lines with a male iron pipe to PEX adaptor. Or perhaps I should start higher up, leave the existing shutoff (but install another) so I can move down to the next threaded connection point if there is a failure like stripped threads, pipe disintegrating, etc. I plan to connect new male to old female since it may be less corroded and less prone to strip(??).

So my main questions:
1. How concerned should I be about disconnecting old pipe from an old coupler and replacing with an new adaptor?
2. I plan to replace the main cutoff valve because I'm concerned that it's old and corroding but is that a baseless concern?

Other options I've considered:

1. Schedule a professional to make the final connection just in case something goes wrong, they would be on hand to fix it immediately.
2. Let scope creep set in and plan to replace the entire line from the street meter to the foundation (a friend recommended this to me). Sounds a bit beyond my budget at the moment.

Any recommendations, questions, tips/tricks/hints welcomed!

 

[Jeff H Young]

I would be confident connecting to those you might be safer trying above the hose bib first and if something breaks work your wat down.
some of what you say i cant understand
?? Let scope creep set in and plan to replace the entire line from the street meter to the foundation (a friend recommended this to me). Sounds a bit beyond my budget at the moment.??
If you can dig trench to proper depth to meter , sure why not I recommend in 2 phases repipe either the service or the inside house not the whole thing at once.

 

[Sponsor]

 

[DIYorBust]

I don't see anything here that suggests you need to repipe back to the meter unless you feel you want to. However, I'd install a new ball valve shutoff where you decide to start piping. Agree with Jeff that you should start a little further up so you have some options if the couplings aren't usable. Exactly where would depend, in my opinion, on physically inspecting the piping, and your confidence and skill, and willingness to repipe back to the meter if it doesn't work out. I wouldn't assume the situation is better at the meter though, so I'd try to limit the scope of work.

 

[Jeff H Young]

I'd probably do the whole inside of house and then the service I'm guessing he has reason for a new service old galvanized would be one good reason, 40, 50, year old pipe is reason enough I think I don't care if underground copper PVC poly I would think it reasonable to repipe it

 

[DIYorBust]

Id probably do the whole inside of house and then the service I'm guessing he has reason for a new service old galvanized would be one good reason, 40, 50, year old pipe is reason enough I think I don't care if underground copper PVC poly I would think it reasonable to repipe it

Yes, I think it would be reasonable.

 

[Helper Dave]

I'd recommend repiping that section like it is, just so you have something solid low on the wall.

But yeah, open up that union, and start taking stuff out to see how easy it is, and what condition it's in. If you can get all the way down to the nipple coming up from the 90, that'd be best. It looks real rusted up. You might need a nipple extractor tool to get it out. I'd be concerned a pipe wrench might just crack it. Lubing it with WD40 or similar for a few hours could help it come out a lot easier. Tapping gently on the pipe can help the lubricant get into the threads, too.

Then repipe that section with brass. Get a brass quarter turn ball valve, as well as everything else you see there. More iron isn't preferred, imo. After the tee with the hosebib, toss in a brass male to pex adapter, and go from there.

 

[Arnold]

Thanks for the replies everyone, really helpful stuff in these comments. And sorry for the lengthy confusing post @Jeff H Young but you covered what I needed.

Another concern I have is whether there is enough room to get a pipe wrench to turn enough to disconnect the pipes, there's less than an inch of clearance from the pipe to the wall but no one mentioned it so I'm figuring it'll just be a bunch of micro-turns.

 

[JohnnyCom]

An offset pipe wrench can come in handy in a tight spot like that.

 

[Arnold]

An offset pipe wrench can come in handy in a tight spot like that.
View attachment 63124

Thanks!!

 

[DIYorBust]

I don't think you're supposed to use WD-40 on a potable water supply. I wouldn't necessarily worry about trying to remove more iron than you need to, unless you observe the old nipples are badly clogged or something. You can worry about that when you redo the service. Otherwise, you could end up doing a lot more work than you planned in order to replace an extra 6 inches of pipe. I do think removing that union would be of some value. After you work on those pipes nearby it could disturb the old union and cause it to leak. But if it doesn't, you're can hold out until the service line.