Wet Bay Heat

Now, if you’re doing the RV thing right, it’s never less than 50ºF outside. But alas, I still have a few years in the salt mines so while we regularly escape to warmer climes in winter, we do have to run a few miles in the cold. The very cold.

The risk is, of course, that some part of the water system will freeze. There are heaters on the tanks, but the manifold and the water pump are at risk.

There is the option to stay winterized until ambient is above freezing and we’ve done that. A couple of gallon jugs with some diluted pink for flushing, water bottles for kitchen use and with the tank heaters on get South enough to de-winterize and enjoy.

Another option is to de-winterize, and heat the wet bay. I have done so in the past by running an extension cord from the right front bay to the water bay, securing it in the subsequent doors, but that is, of course, far from elegant. The best solution would be to have an outlet in the wet bay.  Now, flying water and outlets are not a great combo so I decided the best thing was to put the outlet on the water pump side.

First, to find power. Closest power I could find was two electrical boxes on the ceiling in the storage compartment on the driver’s side all the way aft. There are Romex feeds going in and flexible wires coming out, going into the slides. With some trial and error one box fed the “General Outlets” in the main slide and bedroom, on a 15A breaker. The other box fed the kitchen slide: microwave 20A, the refrigerator 15A and the GFI outlets in the galley at 20A. Of course every model will be different, but similar if you get my drift.

Which one to “borrow” from? All of them are on the inverter so that’s covered. (Not the case on older coaches) The general outlet may have a space heater on it in the bedroom and a bunch of chargers here and there so with another small heater in the wet bay that’s pushing the 15A….. Not sure how much juice the microwave pulls but it’s quite a bit. So I left that one alone too. The fridge circuit can probably take it, but in the end I went with the kitchen outlets as there I have 20A to work with, and I have the most control over the load, ie don’t run the tea kettle, toaster AND coffee maker at the same time. So…. I got some Romex and tied in. Used some bigger wire nuts (the red ones) and made sure that the ground was connected.


Here is the water pump side with the “useless white panel” removed and the Romex snaked in…. There’s a nice big hole where the gas pipe goes aft to the water heater.


Now, the GFI protection in the kitchen is the first outlet… so the feed is NOT GFI protected. Ergo, I installed a GFI outlet on the sidewall….


There you go, safe power. 🙂 (That’s an outlet tester plugged in.)

I ordered this heater….

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It also comes with spacers for wall mount. I mounted it on two 1-by wood pieces, glued rubber to the bottom of them and then laid a length of butyl strip between the rubber and the tanks. This should stay put and there’s no fan/exposed coils. 400W should do the trick.



And to keep an eye on it I’ve installed a remote thermometer. I put the sensor on the manifold side figuring that the heater side will be warmer….


The readout sits on the dash….


Lastly, with my hybrid propane/electric hot water system I am not dependent on the propane hot water heater for hot water…. The run from the manifold to and from that unit, as well as the unit itself are the last exposed pieces in the freezing problem…. I am in the process of re-engineering the plumbing so as to be able to winterize and then bypass just that part….. Description here: Hot Water System


One more thing…… I’ve added one of these thermostats. On at 35/Off at 45. I’ll use this when we’re parked so it doesn’t get TOO hot down there. It’s easy in easy out. So it goes in when we’re driving.

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EDIT…..January 2021. The white ceramic heater was not built for this and has snapped in half…..No workie now. 😦

So I’m running a small plug in 350W space heater in the outlet. Seems to work fine, but I’m going to look for something else…..