Thor Forums

[steve2777]

We have a 2018 Thor Siesta 24ST. Prior to spending the winter in Arizona, I knew we'd be going through some cold nights coming and going to Cincinnati, OH, so I took what I'd hoped would be sufficient protective measures. We would be running the furnace at night, and most of the fresh water system is above the floor, and would be kept sufficiently warm to prevent freezing. However our layout had one "achilles heel": the lines running to and from the water distribution system, which is in the wet bay. The to/from lines run down through the floor, out into the cold air behind the wet bay, then turn 90 degrees into the back of the wet bay to the distribution system. Of course, this means that even though your fresh water tank and 95% of the lines between it and the sinks are kept warm, ALL water used has to pass OUT to the cold outside, through the WDS valve, and back IN to the coach. Knowing this would be a problem, I stuffed the open bottom of the WDS box with insulation, and outside behind the wet bay, I sprayed the water lines with as much expanding spray foam as I could.

Well, not good enough! One evening where the overnight temperature fell to mid or maybe low 20's for a few hours, the system froze and we had no running water, and it didn't unfreeze until well into the afternoon. I hadn't let the water drip overnight because we were boondocking and had low fresh and high grey tank levels. And it simply wasn't that cold for that long, and I'd hoped my protective measures would be enough.

I'm trying to decide what the next step is: If I'd been at a campground with electricity, I could have put my work light out in the wet bay to provide additional heat inside (although that wouldn't have helped the lines hanging out back between the wet bay and the floor). But what's the solution if you're boondocking?

The only other solution I can think of is wrapping the lines and stuffing the
WDS box with electric heat tape. The heat tape I've found is 120V AC, and I COULD wire it to run off the inverter, although that COULD take a lot of watts overnight. I also got several 7 watt 12V heat wafers that I could wire in, and place inside the WDS box, and maybe near the hoses in back if I built some kind of surrounding box out of reflectix to hold the heat in.

Has anyone tried something like this, or come up with any other approaches to this problem? I really don't want to have to winterize the coach, drink out of jugs and flush the toilet with antifreeze, just for several hours of overnight sub-freezing.