2017 Newmar Baystar

“and add sanitizer to the fresh water tank.“

Have you any experience in sanitizing an RV fresh water system? The most used sanitizing agent is bleach diluted to a quarter cup for every 15 gallons. Then you rinse the system. Get experienced help the first time to avoid any trotting.

Hi Mike,

I do not have a Baystar, but I have a Newmar, and I think the items you are asking about are the same.

The valve you are not sure about prevents the water pump from pulling from the fresh water tank. When you close that valve and open the one on the winterization hose, you create a new source of liquid for the pump to pull from.

When you are sanitizing, you want your fresh water tank fill valve to be open, with the other valves positioned as just discussed. That puts your sanitizing solution in the fresh water tank.

When winterizing, turn the fresh water tank fill valve to the closed position. This prevents your antifreeze from going into the fresh water tank and directs it to the plumbing system throughout the coach. With the tank drained, there is no reason to put antifreeze in there.

I also bypass the water heater when winterizing, although some do not. The water heater bypass valves are located behind the water heater, usually accessible via a cabinet door under the sink.

There is a Youtube channel by RVGeeks that has numerous videos I have found helpful with Newmars. They have one that specifically speaks to winterization and would be worth your while.

I think you will find that hose only lets you pump RV antifreeze into the water lines. Usually, to sanitize the fresh water tank you need to pour bleach into the fresh water fill inlet. I haven't seen any RVs where the pump is able to put water into the fresh water tank. The valve associated with that hose most likely only allows selecting the hose OR the tank as the liquid supply to the pump. Isn't that second valve just a drain (to the ground) for the plumbing in the wet bay? To winterize, you first have to change the water heater lines to "bypass" so you can pull the heater plug and drain it. Without that bypass, you would have to fill the entire water heater before the lines got winterized, requiring gallons of antifreeze. Don't forget the icemaker line!