Galvanized pipe and Partial Pex A replacement

[8seconds]

I am doing a complete master bath remodel on my 1961 home with a basement. I want to replace the existing galvanized with Pex A in the new bath and most of the accessible existing pipe. Most of the galvanized is open access and under the floor joist in the basement. I would have easy access to 75% of the plumbing and want to run Pex A through the joists so I can have a flush ceiling when complete.

I can not get to the galvanized going thru the wall into the other bathroom or the kitchen. I had a plumber tell me it is not advisable to have Pex and galvanized mixed in a water system and I should replace it all. I will remodel the kitchen next but I completed a remodel on the other bath 10 years ago and put in new galvanized water pipe. I don't really want to tear into my custom tiled shower in that bath to just replace that pipe with Pex.

Is it OK to replace the majority of the system and leave some galvanized?

 

[Breplum]

Of course it is possible to leave some galv. pipe in place. We never advise it because galv. pipe has past its reliable lifespan, but nothing about replacing the rest will affect the galv pipe. Plan on removing the galv. pipe and map where it all is.

 

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[John Gayewski]

Mixing pipe is fine. It could increase the speed at which your galvanized pipe rots, but I'm not sure by how much.

 

[8seconds]

Of course it is possible to leave some galv. pipe in place. We never advise it because galv. pipe has past its reliable lifespan, but nothing about replacing the rest will affect the galv pipe. Plan on removing the galv. pipe and map where it all is.

Thanks for the reply. I understand the galvanized has a lower functioning life span, but the only section I would leave in is the newer stuff I put in the other bath when I remodeled it 10 yrs ago. Besides functioning lifespan there is no other reason that mixing the 2 in one system would be detrimental to the other?

 

[GrumpyPlumber]

No reason at all PEX will effect the galvy, that said, get rid of as much of the galvy you can, it is one of the worst materials ever used for water or drainage and at 60+ years you're on borrowed time.

 

[8seconds]

Thank you for the professional opinions on my question. Could someone verify the correct transition fitting from steel to Pex A. Uponor catalogue shows a ProPex LF NPT threaded to Pex A fitting for steel to Pex transition. Is this the right style fitting and would there be risk of corrosion with the 2 different materials.

 

[Breplum]

Female or male brass threaded adapter works. Fairly inconsequential galvanic corrosion. It will develop internal rusty build up at that transition (if all the brass angle stops with galv. nipples we remove are any indication).