Damaged pex lines

TKO

Hello this last fall we had a concrete contractor pour our concrete for our new home I had installed the pex tubing for the floor heat. Two days later they returned to cut in control joints, the slab is 4" thick and he sent an inexperienced or irresponsible employee out to cut the joints and in the process he dropped the blade is as much as 3" in many areas, the company came back out and opened up more than 50' along the joints to repair, my question is the lines repaired (because they cut across the lines) they put in about 12" pieces so you have a coupling, 12" pex and then another coupling, how will this effect the flow in the system? the pex tubing is 1/2" so basically your going from 3/8' flow to 1/4" flow back to 3/8" and again back to 1/4" and back into flow of 3/8" all of this within about a one foot span, I also don't trust the system and can see failure if other lines were partially cut or nicked, any input would be great. thanks tim

Gordy

You are correct the fittings will increase head in each loop. Considerably.

Zman

The flow resistance will be reduced. With infloor heat, the flow rates are fairly slow. I would be surprised if it effected performance.

As for the cuts, you would have been within your rights to demand a tear out and repour at the contractors expense. A 3" deep cut is wrong, with or without tubing.

To assure against future leaks, I would pressure test the system very high (100 psi or so). I would also require the contractor to provide a written extended warranty against leaks that haven't shown up yet. You should be able to look for potential nicks by heating the system and tracing the tubes with an IR Camera. The ones that connect to your cell phone like Flir One work great.

hot_rod

How many couplings total?

The tubing manufacturer may have specific direction about burying a splice in the slab, did they wrap the splices?

Was a design done for the system? It would show flow rates and pressure drop for the various loops.
It may require a bit more pumping power, I suspect you will be fine, flow wise.

Rich_49

What tubing manufacturer and what type connection ?

HomerJSmith

I always plan my layout in a serpentine pattern which minimizes the number of tubing passing thru the control joint. I also, drop the tube where the control joint was planned and cover the pex with an electrical grade pvc covering.

Experience is what you get when things don't go as planned!

ratio

HomerJSmith said:

I always plan my layout in a serpentine pattern which minimizes the number of tubing passing thru the control joint. I also, drop the tube where the control joint was planned and cover the pex with an electrical grade pvc covering.

Experience is what you get when things don't go as planned!

I happened to be standing beside the 200A fused disconnect when the concrete cutting guy cut through the feeders with his wet saw. It was an interesting experience.

The PVC didn't slow him down at all—in fact, he didn't even notice he cut them.

Gordy

That’s two couplings per run in the loop. That’s a 50’ swath worth of tubing that was sliced.

So my questions are how many tubes were repaired? If the tubing was 12” centers that’s 100 extra couplings. The question is how many loops...... I think it will deffinetly increase the head of the loops.

Gordy

ratio said:

HomerJSmith said:

I always plan my layout in a serpentine pattern which minimizes the number of tubing passing thru the control joint. I also, drop the tube where the control joint was planned and cover the pex with an electrical grade pvc covering.

Experience is what you get when things don't go as planned!

I happened to be standing beside the 200A fused disconnect when the concrete cutting guy cut through the feeders with his wet saw. It was an interesting experience.

The PVC didn't slow him down at all—in fact, he didn't even notice he cut them.

For a diamond masonry blade rebar is a piece of cake even. The chap would never know if he was cutting pvc. The only indication steel is hit is sparks.........

HomerJSmith

ratio-- Of course PVC is no protection for a dia saw. The purpose for the PVC is because you drop below a 2 to 4" slab and re-enter it. Same reason one comes out of the slab to the manifolds in a PVC 90 so the concrete doesn't abrade the PEX as it expands and contracts. In a 4" slab the saw cut never need to be more than 1 1/4" deep.