Frozen pex line

Rick Kelly

Old timers didn't have to attempt to pass a smaller diameter tube through a larger one that could be 300' long!

Greg Durgin

I got a call from a customer with frozen potable water lines that are pex (Wirsbo aquapex). Last night it turned very cold and it is currently sub zero outside. This is happening on four (2 hot and 2 cold) 1/2" lines run in a joist bay between the first and second floors. They run from a manifold in a utility closet through the bay for about 7 feet then go up into the interior partition walls to the shower and tub.

This is in a recently renovated old farm house and we are pretty sure some insulation in the balloon walls passing by the bays must have been overlooked.There are no fittings between the manifold and the fixtures.

Not a heating question, but I am interested in hearing experiences on how pex reacts to frozen water. Any special advice on thawing?

Thanks in advance for any advice.

Greg

kevin_5

Frozen

Wirsbo doesn't recommend using a torch to warm up their tubing, but since it absolutely won't melt, it's very difficult to hurt it with the recommended heat gun.
I have heated up a 12 inch piece until it was totally clear and rubber like, then twisted it into a big ball and smashed it in a vise to cool. When I take it out of the vise and reheat it, it will gradually unroll, straighten itself out, and eventually snap out round again. All this without even touching it, just the application of heat alone. If you continue to apply heat after it's clear, you can sort of "brown it" like toasting a marshmallow, but it's very forgiving stuff. Just keep the heat gun moving and you won't have any problems. It takes a lot of heat before you even turn it from white to clear, and even that won't hurt it at all. Wirsbo training films even show their tubing being cooled to 95 degrees below zero and beat with a hammer. It doesn't crack. You'll have no problems with a little freezing.
Sounds like they have some work to do in the attic. I recently installed some foil based "low E" brand insulation to the roof rafters of an old farm house. It felt like it cut the summer attic temps in half, although we didn't take actual measurements. It should reflect much of the winter heat loss back into the house as well. Of course we stuffed the balloon walls full of fiberglass at the top and blew in about 18 inches of cellulose over all the ceiling joists. Kevin

Rick Kelly

frozen PEX

You might as well find out exactly where your freeze up is and think about rerouting it or getting some heat into the space where the current tubing resides or else you have a contantly recurring problem. The problem might just be some air breezing across some bare tubing. Some foam pipe sleeving would at least cover that possibility. Worst case: set up hot and cold recirc. lines (gotta be an easier way)

Greg Durgin

Kevin and Rick

Thanks for the feedback. It's good to get confirmation on the toughness of the pex - the customer knows a bit about the heating qualities of pex and will appreciate how it handles freezing.

Those bays should have been completely insulated. Possibly our very good fortune that we went with the pex rather than copper for those branch lines!

As for addressing the future, I'm thinking of slipping some tube insulation over the pipes from an access hole and then the homeowner can find the gap in the insulation envelope and seal it off.

Thanks again for sharing your thoughts.

Greg

Doug Lundgren

Old School thawing

Old timers used to use steam to thaw frozen pipes in the good old days before electric thawing machines. Small gas can (metal) can be rigged up as steam pot, with small (1/4") tube at spout. Attach a suitable length of clear flexible tube to this spout. Heat small amount of water in pot to boiling, steam will travel through tube which can be inserted in end of bay. Steam will thaw frozen pipes quickly, with no risk of fire damage from torch.
This method very reliable, and may come back as Pex becomes more and more popular.