Winterizing Tankless Water Heater (Using Nautilus Panel)

[ThomasB]

Hello to all fellow campers! I am a little confused as to how to perform the winterization on our 2022 303RLS. I winterized our fifth wheel last November 2022 first by blowing air through the "City Water" hose inlet, and Nautilus panel set to "City Water", then opening ALL taps inside & outside RV (including toilet). I also opened the "Drain Plug Cover" on Tankless Heater as well to rid any water there. Using the "Winterize" settings on the Nautilus panel to suck antifreeze from a 10 Litre jug of antifreeze, I opened all taps & toilet until I saw pink. I have always had a 6 gallon water heater in our past RV's that I drained before winter, no worries. With the new Tankless heater I am concerned that if not winterized properly that any remaining water left inside water heater may damage the unit. Any tips would be greatly appreciated before cold weather sets in. Thanks for all replies in advance!

If you ran antifreeze through the system, you have it in water heater as well as the lines. Just draining it or blowing out the lines won't remove the water from the small (1 quart or so) mixing tank in it. You did right by running antifreeze through the lines.

 

[BillandLisa]

If you didn't get pink stuff coming out the drain and filter ports on the hot water heater you can still have issues. The Winterize settings that you used when pumping antifreeze, bypass (isolate) the hot water heater (bad). you need to pump antifreeze with the valve to the hot water heater in a "normal" vice "isolated" position (it was the Red valve on my nautilus - but you should be able to figure out which one it is on yours as it will be in the only valve that is only in a different position in the winterize graphic. (original purpose of the "winterize" line up was to isolate the HW tank to prevent having to pump 6-12 GALLONs of antifreeze to fill the HW tank. On a tankless system, you just have to fill a small mixing bowl - air does NOT remove all the water from this bowl as both the input and exit lines to the bowl are in the top allowing air to flow into and out of the mixing bowl without moving the water in the bottom of the bowl.

Step by step instructions provided in post # 10 and some great follow up with pictures in #17