Pex pipes

PEX tubing (cross-linked polyethylene) is freeze resistant. It can expand up to 3 times it's dia. and not burst. If it expands from freezing or is kinked back and forth, it will return to it's original shape as it has a memory. Amazingly tough stuff.

PEX fittings like couplings and elbows are made from a type of plastic called polysulfone which is also freeze resistant.

It's the method used to join PEX to fittings that can be the problem after a freeze-thaw cycle. Pinch clamps, being metal, can loosen and end up leaking. Same thing with copper crimp rings if you have them. Faucets, toilet valves, filters, etc. would be susceptible to damage as they can have metal components or different types of plastic which are not freeze resistant.

PEX is damaged from exposure to UV rays and becomes brittle. Our TT has hot and cold low point drains hanging down about 6" at the very rear and are exposed to UV a lot of the time. Not a smart location to put them. With some water left in them, they could potentially split when frozen. When I eventually take the coroplast down, I'll do something with them as a precaution.

There is a You Tube Video.. A plumber took several assorted brands of PEX, also a copper tube, Filled them all with water and applied shark bite fittings to the ends (One end before he filled, one after) put 'em in the freezer and let 'em freeze solid.

Then he took them out. .On the copper tube the shark bite had been pushed off one end by the expanding ice as it froze.

on the pex they looked same as they did when he put them in save a bit "Frosty".

He cut them open showing the solid ice inside.

PEX freezes very well, it has enough give to survive,, I've frozen mine a couple (2)of times and not had any problems once thawed.

What does NOT freeze well is the elbows and connecters on the end of the pipe.

For this reason it is suggested if you are subject to freezing you open all valves and blow, Gabriel, Blow (Sorry could not resist that line) using an air compressor with a regulator (Set to like 50 PSI) blow the lines out till you run out of air (I use a 4 gallon tank type,, You must use a tank type) or you no longer get water out the low point drains.

Wait for the thing to re-charge and blow again, and again.. like five to 10 times.. After the first blow or two cycle the ice maker manually to drain it back into the lines,, Run the water pump for oh, a minute (dry) to empty it into the lines then blow again.
(Also before you blow drain and bypass the water heater)

Some folks worry about the tiny amount of water that will remain in the lines, Don't. the low points will be PEX not connectors save for the low point drains and those are open so their low point is THE GROUND.

Now pink (RV antifreeze) drains, and toilets.. Job done. You will need 1-1.5 gallons depending on your floor plan (1.5 bath 1.5 gallon).

smkettner wrote:
... Outside shower is always suspect.

True- for that reason I added an isolation valve for it.

Not sure how other RV's are made, but my TC has factory valves to isolate the hot and cold feeds to the outside shower. The city water inlet did not. I added a valve for this water input line to isolate it.



For winter preparation (after summer use of outdoor shower and city water inlet) I will fully winterize the domestic water. Once the system is full of RV antifreeze (RVAF) I will then close the isolation valves on each of the shower hot/cold and city water inlet. I leave the camper this way until I need to use in winter.

When ready to go for a winter outing I keep the isolation valves closed keeping RVAF in the small pipe portions that lead to the exterior components. I then fill the water tank via the standard cap fill and use the pump to dewinterize as normal.

Those little pipe spaces that are filled with RVAF helps keep the cold from transmitting into where the water is. I also bring the whole outdoor shower head and hose to the inside during winter even though it was flushed with RVAF and then opened up to drain any fluid out. I stuff some insulation of sorts in the space where that outdoor shower head would normally be stored.

fish0821 wrote:
This will be the first time I winter in the camper. Will the pex bust if it freezes?

Thanks in advance.

While in use you are not going to freeze much until below 25F. How cold do you expect it to get? Outside shower is always suspect.

A friend bought a 5er. Even though she knew I had owned an RV for years, she didn't ask how to winterize. She just "assumed" that opening the low point drains was sufficient. She was lucky. She only had to replace the shower head and valves. All of the pex tubing was fine.

colliehauler wrote:

bka0721 wrote:
I wouldn't worry about the Pex pipes as much as they are not the weakest link of the water chain. I would be more worried about the appliances the Pex pipes supply. Such as faucets, Heads of showers and Toilet connections.

b

And last but not least the water heater. Why not winterize?

Didn't think furnace would quit!!!
This year will shut off water and drain everything.

bka0721 wrote:
I wouldn't worry about the Pex pipes as much as they are not the weakest link of the water chain. I would be more worried about the appliances the Pex pipes supply. Such as faucets, Heads of showers and Toilet connections.

b

And last but not least the water heater. Why not winterize?

I wouldn't worry about the Pex pipes as much as they are not the weakest link of the water chain. I would be more worried about the appliances the Pex pipes supply. Such as faucets, Heads of showers and Toilet connections.

b

I have experienced Pex freezing last winter with no issues.
I had removed all existing water lines and plumbed all water lines with Pex, before heading south.
I winter in southern TX, while there my furnace decided to quit working. When my son-in-law checked on my house and found no water flowing from the spigots. He shut off the city water supply inside the home, shut off all gas lines, opened the most upper and most lower spigots, opened the drain on water heater and left.
Upon arriving home in April the only problem was a frozen and split ball **** shutoff before the water meter, also frozen water meter.
Luckily the ball **** was split above the ball so no water would flow. Had city shut off outside, changed ball **** shutoff and water meter. Everything else held secure thanks to the Pex. That experience made me a believer in Pex

dbbls wrote:
Pex won't break but the joints will.

Ditto.

But it will take a hard long freeze. I have been in the 20's for a couple of weeks now and water in my camper freezes (slushes) but the daytime is warm enough to thaw and not cause damage (yet.) Will winterize this weekend.

If it had been in the 20's the whole time I would be concerned.
Don't rely on my experience- DYODD.