Frozen anti-freeze

Illini83

I'm in the process of winterizing my 2023 TAB 400 for the first time. I live in Wisconsin and I've seen temps down to -27F, so I want to make sure I'm minimizing my chances of damage to the PEX and fixtures in my camper during the winter.   I've done a very thorough  job with the blow out portion of the winterizing process, but I'm worried about residual water in the faucets (I lost 2 faucets on outside walls in my 50F heated cottage, 2 winters ago, even when I drained all the water from my plumbing system)

What I learned is the rating on the RV antifreeze  (-50F, -70F, -100F) is the temperature that will cause a sealed copper pipe, filled with the antifreeze, to burst. (I don't know the wall thickness of that copper pipe.) What some manufactures do note, is the burst temperature for PVC or PEX is significantly HIGHER than for the copper pipe. (I have not found any information that states the burst temperature for PEX when filled with -50F antifreeze.) See this link for an example: https://www.westmarine.com/on/demandware.static/-/Sites-wm-master-catalog/default/dwc68f69b3/images/legacy-pdf/LI136WMAntiFreeze101_V10.pdf?srsltid=AfmBOoo7-jGzkmuloHy_cAhbMF_hhM3LYBVsBJVAawsk2I9skh3WRJai

My takeaway, living in Wisconsin, where I can count on temperatures hitting -10F every winter, is I should be using an RV antifreeze with a -100F burst rating in order make sure I don't burst any PEX in my TAB 400. I would be living dangerously using a -50F or -70 rated antifreeze. 

Bill&Suze

I just read the label on the RV antifreeze I have. It's rated to -50 burst temperature. The bottom of the label states that it will freeze at zero degrees F but that it will not harm plumbing. Perhaps what that implies is that as it freezes at zero it also contracts. There was no further information regarding when a slush state occurs, either before reaching zero degrees or at that point. In recent years, it's been a rare winter when we've dropped below zero here in southern coastal Maine. There was a time when we could count on dropping lower but we have definitely warmed.

Basil48192

Just one more comment to add to the confusion!
Last year I purchased some blue antifreeze from a local marina/boat service center near my home.  It was rated for -100°F and was definitely propylene glycol based.  I thought it was a better choice than the standard pink stuff.  I have a 2021 T@B 320s with the Nautilus system.  
After blowing out the water, I tried to 'suck' up the antifreeze...but my pump couldn't pull it out of the container.  I've never had trouble in the past, so I kept trying but it just wouldn't work.  I ended up flushing everything with clean water, then repeated the entire process with the pink antifreeze.  It worked fine. 
I'm not really sure why it didn't work....but I assumed that the viscosity and/or low coefficient of friction of the expensive antifreeze prevented my pump from developing enough suction to pull it through the system.  Anyway, I thought the story might save someone a little money and time in the future.