burst pipe protection?

It says that it cannot be used with PEX which is the kind of plumbing in our RV.

Weird...

I don't get it...

After reading their FAQ's, the liner is placed inside tradition plumbing in a home. The test system has only been going 15 years. Some parts of the system may only last a year or two.

A person would have to be nuts to use the system. The liner would cut back drastically on the amount of water-flow (volume).

pex will freeze and not break the problem is the fittings thats the part that breaks.

I've never heard of it. And, it may be different, weird and questionable.
But, it's a step in the right direction. Maybe in the future RV's will not have to be winterized. JMO

They call it a "liner" but I don't think that's what it is. It's a small diameter foam rod. No water flows through it - it just takes up space in the pipe. When water freezes inside the pipe, the foam rod is compressed. The compression takes up the space of the expanding ice so less pressure is exerted against the walls of the pipe by the ice.

I once saw something similar - before lead pipe was outlawed, they used to sell an oval lead pipe. The oval would expand to a cylinder when water froze inside the pipe. The volume of the cylinder was greater than the volume of the original oval pipe. It was good for one or two freezes according to the literature.

As far as I can see it is not available for RV's as the non compatible pipes listed are all RV type pipes.

I see little value if only because you are going to need to winterize anyway because of the valves and other places where the foam core is not going to protect.

It appears to prevent burst pipes.... no actual freeze protection.


On edit:
Since your RV is about always in use... IMO best to prevent freeze ups completely.
This is where I plug for keeping the hot water moving around. The cold pipe next to the hot should stay warm enough.

Electric pad heat can also be added if you have access and the 12v power.