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[DenverTransplant]

My 2017 ACE 30.1 has a “heated” wet bay (e.g. there is a hot air duct from the heater into the wet bay), which leads you to think that there is some degree of freeze protection for the black and grey tanks. However...

I was under the rig a couple of weeks ago running wire for a Bogart battery monitor and was a bit surprised to find that the grey tank dump line is fully exposed to outside conditions. The line comes out of the “floor” of the unit about 10-12 inches into a 90 elbow and then runs about 18 inches into the wet bay to the grey water dump valve. No insulation, or protection from the weather other than being tucked up under the body.

Seems to be a very weak point in the design as when its cold out, the line is fully exposed and is going to be the place where things will freeze up first. I don’t use the rig in the winter (or at least woudn’t use the water systems it until I got far enough south), but it was a wake up that the heated wet bay won’t help in preventing a freeze up of the grey water dump line. Effectively the coach water system isn’t really protected.

I suppose you might be able to dump a gallon or so of anti-freeze in the grey tank first, but I have low confidence it would actually stay in the low points of the system. I’ll have to check the specific gravity of RV antifreeze. I’d rather find something heavier and not miscible with water. In my refining days, we used to fill instrument leads with a wonderful thing called Krytox which had a gravity of something like 2.0 But its about $300 a pound or more. Anybody know of something like that, but which is a whole lot cheaper?