Backing Up Antifreeze in Shower Drain 2021 Spirit 26T

[Tom8905]

I usually chase the weather, but this year I’m having to do a little winterization. I poured antifreeze in all of my sinks with no problems, but when I did the shower the antifreeze backed up in the shower. The shower drained water fine last night. What is the deal? 2021 Spirit 26T

[Morich]

My first thought was that you might have what they call a "waterless trap"! A gizmo that I am not fond of as it is a plastic item which I don't trust.
But in looking at the interactive parts drawings here, I find you have the normal trap:
https://catalog.winnebagoind.com/menu/Parts.htm
Click this snip for better view?

It looks like the normal trap, so I would have to move to either the line is clogged for some reason??? Doesn't sound true!
So the next bet might be that the front of the RV might be tilted upward?

It looks like a fairly long horizontal run from the trap to the tank. Is it tilted enough to keep water from running to the tank and fills back into the shower floor? Maybe a pretty steep left/right tilt?
Best guess there!
Things are in a mess in the world but I "think" water still runs downhill?

[Tom8905]

Those are some great pics! I’m going to have to check that link out! As I said, the shower drained fine last night. I didn’t think it was that unlevel, but I’ll play with the levelers tomorrow. Thanks.

[Eagle5]

Hi Tom & Richard,
I believe I too have that waterless trap in my Minnie Winnie. When I take a shower, it drains fairly well, but sometimes when adding antifreeze, it does seem a little slow. Perhaps the inertia of water coming down the drain in volume helps keep the one-way valve open?
Regardless, just having a little antifreeze in there should protect things well.
The Gray tank is pretty-much empty, right?
Thanks, Eagle5

[Tom8905]

Greetings Eagle5. Yes, all tanks emptied and got about 1/3 of a gallon of antifreeze in the shower before it started backing up. It may be slowly going down but not so I could tell. I’ll check on it tomorrow. Only supposed to get around freezing or just under for the next few nights. Thanks.

[Eagle5]

It really sounds like a hair ball or something like that plugging it up. Perhaps hit it with a Plunger and see if it starts flowing?
Also, you only need a small amount down the traps. RV Antifreeze will protect to 20ºF with just 15% antifreeze & 85% water.
Here is my winterizing process, if you are interested:
Winterizing a 22M using the blow-out method

[Tom8905]

Okay. Eagle5 and morich were both right! When I returned to my MH this morning the antifreeze wasn’t standing in the shower so it must have been draining very slowly. Partially clogged maybe. I added a little more until it backed up again. Then I jacked up the left side and the rear with the levelers and voila! The antifreeze went down and I was able to pour a steady stream down the drain! I didn’t realize it was that unlevel but I guess it doesn’t take much. Also had a little water run out of my water heater drain. Thanks to all!

[Morich]

Sounds good!
And most of us have been a little off-level at times!
I'm beginning to find it normal!
Enjoy the winter!

[dkoldman]

FWIW, my WBGO manual says to only pour one cup of the RV antifreeze for the P Traps. Also, I don't think the intent of the antifreeze has anything to do with freeze protection rather to trap the odors from the holding tanks.

I drive my RV year around. If it is winterized when I get back I add a cup to all of the p traps. If you drain the toilet properly with pump on, there is no need to try to put antifreeze in toilet.

Check your manual to see if it confirms what I say, your coach may be different.

[Tom8905]

Thanks dkoldman! I’ll be back in mine in about 2 weeks, but was in a couple of nights of just below freezing temps with no power to MH. I wanted to add enough antifreeze to take care of the trap and the tanks at the dump valves. May be a little too much but I had a frozen dump valve a few years back and had to use a hairdryer to thaw it! If I was in the UP of MI or somewhere further north I would be more thorough, but hopefully this “mini winterization” will be good enough until I can head further south. Thanks again!

[Morich]

With me, many things we do are like going to a casino?
We have to look at the risk/reward factor and decide how much we want to lay on the line. What does it cost versus what does it to be safer versus what does it cost if we are too short?

Not putting antifreeze in the tanks is one example. What does it cost to make sure any water left in the holding tank doesn't wind up down in the valves and freeze?
If we shop the antifreeze, it may cost 50 cents to protect a tank valve. And what does it cost if we avoid spending that fifty cents? OUCH!
If the weather is not very bad and there is not much water left to settle in the valve, I might get by, but is that a gamble you want to take in your area?
If money is not the object, how much time are we laying on the line? If the antifreeze jug is in hand, pouring a cup in the stool to protect the valves is near a minute versus how long to change out a frozen valve? OUCH again?

But I also admit to not wanting to work harder than needed! If I wanted to drain the black tank and make sure it was totally drained, then leave the valve open so nothing could collect, I might be fine without antifreeze in the tank. But that involves lots of things like the potential of dumping a bunch of "BLACK" in my yard. I don't want to deal with that, so I close the valves.
I find it much easier to just add the cup of antifreeze and not do the dirty of dealing with a pile of "BLACK" in my yard!