Winterizing the macerating grey water drain pump on the Navion?

[Free Ranger]

I’ve been doing the winterizing deed on our 17 Navion for a few years now, but I’m never quite comfortable with feeling like I’ve gotten all the water out of the macerating grey water drain pump in this system that Winnebago used on this model. The macerating pump itself is virtually inaccessible. If I drain the tank using the pump until no water comes out, let the coach sit for a few hours and then activate the pump again, I will always get some more water out.

So, I’m curious as to what other similar Navion model owners are doing with regards to winterizing their macerating pumps other than flooding it with antifreeze?

[Goodspike]

Not familiar with the system. Can you use compressed air? But whenever you're talking about a pump I think antifreeze is the solution. That's part of the reason why I run some through the water system pump after blowing the system out.

[Morich]

Keeping plumbing alive is always a bit of a game but it does look like they thought of that problem.
Have you been able to access the parts drawings to look how things are laid out on your RV? Lots of good things to look at here:
https://catalog3d.winnebagoind.com/menu/Parts.htm
If you drill down far enough to get a look at the pump, it may ease your mind a bit as it seems to be tipped to drain and a port to get the last portion out of the line and pump. Looking through from the back, this is what they show. Looks like that should do the job?