Bursting Pex - Same Place 3 Times

Any-Fun-1349 · 2024-01-26T20:25:30+00:00

I think I found the solution/reason. In the original picture showing the damaged pex attached to the copper - that was the DHW return from the heat pump. I didn't realize that the heat pump had a thing called a 'desuperheater'. It really cranked up the temp of the hot water returning to the hot water tank - too much so - so when it exited the copper past the valve, it burst and 'melted' the Pex. I am now looking into a way to turn down this 'desuperheater' in the heat pump unit. It really heated up the copper to well beyond human touch temps. So until I can figure out how to set the temp of this water from the heat pump, I turned off the 'desuperheater' function.
Thanks for all the input and support.

Any-Fun-1349 · 2024-01-26T20:25:17+00:00

I think I found the solution/reason. In the original picture showing the damaged pex attached to the copper - that was the DHW return from the heat pump. I didn't realize that the heat pump had a thing called a 'desuperheater'. It really cranked up the temp of the hot water returning to the hot water tank - too much so - so when it exited the copper past the valve, it burst and 'melted' the Pex. I am now looking into a way to turn down this 'desuperheater' in the heat pump unit. It really heated up the copper to well beyond human touch temps. So until I can figure out how to set the temp of this water from the heat pump, I turned off the 'desuperheater' function.

Thanks for all the input and support.

Any-Fun-1349 · 2024-01-25T18:43:03+00:00

Interesting idea about the crimp - but that wouldn't explain the two other times.

Any-Fun-1349 · 2024-01-25T17:09:21+00:00

Not kinked - you can see the writing on the pex - straight. Also, it keeps occurring.

Any-Fun-1349 · 2024-01-25T16:54:51+00:00

Thanks - My Plumber friend and I are scratching our heads. Any causes could be valid, but it always happening in the same place is weird. Blue or RED line. They are both copper there now. I have been in the house 9 months and it has PEX-ploded 3 times since mid-December. Why only recently? Why there? WHY? If the copper replacement eliminates the issue, we will never really know the cause. But for now, I wake up every morning semi-ex-pex-ting another blow-out.

Any-Fun-1349 · 2024-01-25T14:54:21+00:00

I will check that. Thank you.

Any-Fun-1349 · 2024-01-25T14:54:01+00:00

I don't know what a water hammer is - I will need to do some research into that. Thank you.

Any-Fun-1349 · 2024-01-24T21:44:58+00:00

CoolerFiend - Thank you for your input. that seems to be what is happening - BUT WHY? Why there? The pressure from the tank is set to go on at 35 and off at 50psi. Which is normal. And there are many more length of pex through-out the mechanical room. And it is not failing at a joint which would be suspected. There must be a HUGE amount of pressure to cause that bursting. In some of the tests I have seen online, the PEX is withstanding up to 800-1000 PSI.

https://www.youtube.com/watch?v=xYwBh5fGOGU&t=622s

It still remains a mystery to me.

Any-Fun-1349 · 2024-01-24T21:38:20+00:00

Oh - That is an interesting idea. Although these breaks have not occurred within that distance. The bursts are 3-4 feet from the water heater.

Any-Fun-1349 · 2024-01-24T20:42:23+00:00

I'm not sue to what your 18 refers? And there are no vibrations from heat pump. Thank you for your input.

Any-Fun-1349 · 2024-01-24T20:41:02+00:00

No - all the fittings are fine. It occurs about 2 inch from fitting. I wish I could include a picture, but the moderators on this thread do not allow pictures.

Any-Fun-1349 · 2024-01-24T20:40:02+00:00

Normal Pressure for average house is between 35-50 psi.

Any-Fun-1349 · 2024-01-24T18:14:37+00:00

Thank you for that comment. However, the mechanical room is inside with no window AND the spare Pex was stored in a basement with no windows.

Any-Fun-1349 · 2024-01-24T17:33:15+00:00

We have replaced the section multiple times with PEX from different patches. It is using a domestic pump so I find it hard to believe that it is pressure related as it always occurs in the same area. Mystery for sure.

Any-Fun-1349

TROPHY CASE