How to replace corroded PEX fittings embedded in wall

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What causes corrosion on PEX fittings?

PEX fittings are made of brass and are much resistant to corrosion, except in some cases.
In this one, these 20-year age fittings were embedded in mortar behind the tiles, and it's this contact with mortar that caused the corrosion.
Similar fittings of the same age within the same PEX tubing installation and which are simply free from any mortar around them, did not get corroded.
These corroded outlets were found leaking behind the wall tiles and down to the floor below floor tiles,then causing a water infiltration through the slab down to the underneath ceiling of the lower apartment.

How to replace the corroded PEX wall outlets and avoid putting mortar around them (continued from part 1)

Step 5: Install surface mount PEX wall fittings

Surface mount PEX elbow outlets are used as shown here. 
Hold the outlet and mark the holes.
Drill them and fit wall plugs.
Temporarily fix the outlets with screws.
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Measure the length of the small tube.
Unscrew the outlet, fit the tube and fix again the elbow to the wall.
Note: don't forget that the height of the wall outlet is the one of the shower mixer. Make sure such height is convenient and that both outlets are fixed at the same level. Also consider fixing your outlets at the same spacing than the existing ones.

Step 6: Make a leak test and prepare for the shower mixer installation

Both outlets have now been fixed.
Open the water tap and let it flow for a few seconds.
Temporarily plug the outlets then open the taps again and leave them for a couple of hours as a leak test.
Now proceed as shown for temporarily fixing the mixer.
Cover the 1/2" thread of the eccentric with one layer of Teflon tape.
Add one layer of plumbing hemp. It will help blocking the rotation of the eccentric.
Cover the hemp with a thick layer of Teflon tape.
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Mount the eccentric into the wall outlet and adjust it as shown below.
Measure the distance between your outlets after each adjustment until it matches the one of your shower mixer. Try the mixer by screwing it in by hand to make sure it fits well then remove it.

Step 7: Time to cover up the broken tiles around the shower outlets

There are several ways of repairing or covering the broken tiles:
  1. Re-tile but then you face the same problem upon the next repair with the need to break the tiles and the concrete
  2. Install a marble plate 
  3. Install an acrylic plate (Plexiglas)
My choice is for a 10 mm thick acrylic plate which is shown in the below pictorial.
Start by taking the necessary measurements. 
Now drill the openings in the Plexiglas plate.
Fix the plate with silicone sealant. Note well the spacers that have been used to keep the panel a bit away from the wall.
Complete the installation by fixing the mixer. Wait 24 hours before using it.
The job is complete, elegant, practical as it allows to intervene in the future without having to break tiles. 

See also our other tutorials on mixers, taps, plumbing, PEX tubing, etc....

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