Winterizing questions in a 400 (2019)

RCB

This has probably been covered, but my search didn’t turn up much. Apologies if this is duplication. I have just completed  my first winterizing and am left with the following questions.
1. Opened the yellow drain to the Alde hot water tank but not much came out. How can I tell if it is empty ?
2. Drained the water tank and pumped “coolaid” thru the system using the bypass valve and a Camco bypass kit so there is none in the tank. I tipped the trailer up at the front and adjusted so the drain was lowest at the back and driver side. Is the tank empty and should I be concerned about a small amount (if any) of water  left on the bottom of the tank ?
3. Just forward of the water tank drain there is a short black 1/2 “ hose extending down a couple of inches and has a red fitting on it. What is it for ? A vent for the water tank perhaps ?
4. Last query. This morning was cool and damp. There was a film of dew on the outside and on some surfaces on the inside. Presumably, on the inside, it all evaporates as the trailer warms up. To promote warming should the blinds be left open somewhat ? Should the head vent be partially open ?
Thanks for any comments you might have.

N7SHG_Ham

The red plug is the Alde glycol drain, only remove that when draining and replacing the Alde glycol fluid.

Sharon_is_SAM

Your Alde water tank empties best if you first pressurize your system via the pump.  Don’t open any faucets before you open the Alde yellow drain.  Start with a full Alde water tank, place a measuring bucket under your Alde drain. You should get about 2.5 gallons.  A little left over won’t hurt. 

A little water will probably be left in the tank and should not hurt.  Just make sure your drain valve is dry.  Did you use your pump to move the Antifreeze?   If not, and it’s tge same pump as the 320, you need to unscrew your pump lines and empty them and unscrew/dry your pump filter.

Regarding the condensation, if the trailer is properly dried out, I don’t think you should have condensation in an unoccupied trailer.  It will lead to mildew and mold.  You want to promote ventilation, so crack a roof vent at a minimum and consider some Damp Rid.  

ScottG

Ditto what Sharon said regarding the Alde drain. I've also had a few experiences where I've opened the yellow drain valve and nothing has come out. Closing the valve and pressurizing the system (either with water or air) seems to get the flow started. If I have the system pressurized and I open the Alde drain first, the hot water tank will usually drain without incident.

Unfortunately, the only way to know the tank is empty is to physically see it drain.

Cccjim

I have no clue if my Aldi hot water has adequately drained on my 2021 Tab 320 S.  I have read this thread. I have blown out each line as the nautilus system directs. Considering my undiagnosed OCD, not being sure drives me crazy 😔

Sharon_is_SAM

It helps to have a bucket under the Alde drain so you can measure the volume.  The Alde rep did say that a little water left behind will not hurt as there is room for it to expand.