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Winterizing a Nautilus P1 System.


These days, a lot of higher-end RVs have water management panels such as the Nautilus P1. While they do make water management tasks easier, it can sometimes be confusing on how to winterize them. This page then attempts to make the winterization process easier to understand. Note that this page and attached video should be used as a reference only - you should follow the winterization instructions from the manufacturer.



Read and follow all manufacturer's instructions. Failure to do so can result in freeze damage.


If you do not have a copy of the winterization instructions, you can download them here, The winterization instructions begin on page 9.

There is no need for me to replicate the instructions, so I will provide you with a few comments.

  • When I winterize my coach, I drain the fresh water system and water heater first. I temporarily replace the plug back into the water heater when it is empty.

  • Next, when blowing out the lines, I open one faucet at a time (step 2 of the instructions is not clear - and seems to suggest opening all of the faucets at once).

  • In step 4, the instructions say to put the RED, BLUE, GREEN, and WHITE valves in a 45deg angle. Conversation with the manufacturer reveals that this allows the water line from the fresh water tank to be drained.

  • When filling the system with RV antifreeze (step 9), I found that sitting a jug of antifreeze on the ground will likely cause the pump to lose prime. Either place the jug higher or adapt a boat-engine antifreezing bucket like I did (as shown in the video).

  • Again, according to the manufacturer, in step 14, rotating the Blue, Green, and White valves will force antifreeze into the fresh water tank.

  • The RED valve is the water heater bypass. In the horizontal position, the hot and cold water lines are connected together - just like a conventional water heater bypass.


I also run a bit of antifreeze into the fresh water tank with the Sanitize function - which can also be found in the instructions. Finally, I pump a bit of antifreeze into the black water rinse port. As well, this is not covered in the instructions, and I was not happy with blowing air into the port as I could not tell if the water was completely removed or not. There is an anti-siphon valve in the line so the only sure way I have to ensure the line is protected is by pumping in a bit of antifreeze.

The antifreeze jug I used came from a Camco 65501 "Do It Yourself Boat Winterizer Kit. I modified the kit a bit by shortening the hose so it would be easy for the pump to maintain prime. A hose adapter can be found at most well-stocked hardware stores.


Winterization Video





Nautilus P1 Manufacturer's website
Nautilus P1 Owner's Manual


Last reviewed and/or updated May 10, 2017