Where does this drain pipe come from, and where does it go?

[S.Rodimus]

We just winterized our rig. Not the first time we've done it, so I'm pretty confident we're all good. But I'm confused as to where this pipe/tube comes from and goes? It's in the water center, you know, where we fill the fresh water tank and drain the waste tanks. We don't have an outdoor shower, but if we did, this is where that would be connected. Owner's manual instructs us to open these 2 valves when draining the whole system for winterization, but...they don't seem to be part of the drainage between the kitchen/bathroom sinks and the gray tank, nor between the shower and the gray tank -- because when pumping antifreeze through the system this pipe/tube doesn't fill at all. It only fills when we open the 2 drain valves that are on it. So, please help -- what is this?

PS: What direction are the valve handles supposed to be in for normal plumbing system operation - up/down, or left/right? (We had them in the configuration shown - up/down, and everything worked fine. But looking at it now, that seems like a "closed" position meaning no flow?)

PPS: Was I supposed to fill this tube with antifreeze for winterizing,or leave it empty after draining the system of water?

 

[Morich]

Not the better type drawings but this looks like what I think I see!
Plumbing drawings here:

https://www.winnebago.com/Files/Files/Winnebago/Resources/Diagram/2007/07_726a_plumb.pdf

General location and next left from water in port, I see two rubber plugs. On some RV there would be an option for an exterior shower here with faucet valves in these holes.

View from rear WITH faucet

And what I think you have with different option.

I would guess the two plugs fill the hole for the faucet handles and then there is a tube drain going down. The two small white handles in your picture likely let the water drain from this pipe and go out the drain below!

Guessing, I would expect turning the handles to align with the pipe will let water go out below? without the drain, this low point in the line will hold water due to being a place where it would have to go UP to get out the other drains?

 

[S.Rodimus]

I *think* so, Morich, but when I turn the handles the water (or now, antifreeze) seems spill out over by the black and gray tank release area. I haven't yet been able to determine where exactly it's flowing FROM along this pipeline, nor do I see any drains directly below the handles. No more daylight here today, so I'll perhaps investigate more tomorrow. I also can't figure out where this tube is sucking its antifreeze from (when I turn the handles, it fills with antifreeze). I'm guessing somewhere upstream in the plumbing system generally. The diagrams (which I already have and have tried to study) are hard to figure out exactly.

 

[l1v3fr33ord1]

S.R-

According to the plumbing diagrams, the left-most (forward) valve is the hot water low-point drain valve, and the right-most (aft) valve is the cold water low-point drain valve.

There should be a single drain pipe between the two, sticking out through the floor of the wet bay, to dump the drain water on the ground. Your visual inspection will confirm this.

Having the drain valve piping full of antifreeze upstream and through the valves is a positive thing. The fact that some antifreeze remains in the drain section (between the valves) is a bonus.

 

[S.Rodimus]

S.R-

According to the plumbing diagrams, the left-most (forward) valve is the hot water low-point drain valve, and the right-most (aft) valve is the cold water low-point drain valve.

There should be a single drain pipe between the two, sticking out through the floor of the wet bay, to dump the drain water on the ground. Your visual inspection will confirm this.

Having the drain valve piping full of antifreeze upstream and through the valves is a positive thing. The fact that some antifreeze remains in the drain section (between the valves) is a bonus.

Hot water low-point drain valve and cold water low-point drain valve makes sense, moreso if we had an exterior shower installed there. But we don't. Still makes sense, though, that we'd need a low-point drain for cold and hot there, even without the exterior shower.

There is also definitely no drain pipe between the two valves, though it's possible it is draining at that point and the pipe is just missing (it's an old rig).

When we open the valves, liquid falls to the ground near the black/gray drain area -- we just haven't yet been able to determine where exactly it's exiting the clear tubing in the first place and what path it's flowing from there to the black/gray drain area.

I took another look this morning in daylight, and I think I still have more examining and learning to do. Because what's confusing me now is the 2 tubes that extend from this valve area, over towards the water fill connection area -- one connects to the water fill inlet itself, and the other connects to the "Normal/Tank Fill" valve. So would I be correct in understanding that when I fill my Fresh Water Tank, the water flows from my garden hose as follows? --

Here is the view from below of those 2 tubes connecting to the water fill inlet itself, and to the "Normal/Tank Fill" valve:

 

[Morich]

Sounds like any one of those pipes above may be frozen. Getting to the spot is likely going to be tough.
But there should be a drain sticking down from the center connection if it is as shown???

What happens when you open those two white valves? I would expect water to come out the bottom.
But to find the leak, the side will have to be taken apart to get to the pipes above. OR there are times when pulling the inside wall off is better?

If the lines were not drained well and there are leaks now from freezing, it could be any one of the pipes in the red area.

Which location may let the water run to the side and fall where you can see it will often depend on how the RV it parked and which side is down. A small leak from a crack in a pipe can follow the pipe quite a ways before dropping off to run along the floor or whatever it is on before coming to a spot where it can go further down!

I ,ight start with looking at the pipes that go up the outside wall as they tend to get less heat than some of the others but that depends on how long and how cold as well as where heat might have been placed!

 

[l1v3fr33ord1]

S.R.-

Tee "T-22" is in your first photo, between the two drain valves. Whatever comes out the drains when the valves are open goes through that tee and then exits the tee out the leg that's almost out of view, pointing towards the passenger side of the coach. On the diagram this is drain tube "TU-8." According to the Water Parts Identification List (link here):

T-22: 000156326 / 326721-01-000 TEE 1/2" PEX X 1/2" PEX X 1/2" MPT
A-15: 123152-01-000 ADAPTER-SWIVEL 1/2" FPT X 1/2" BARB
TU-8: 112176-01-000 TUBING-FLEX X 1/2" ID, 5/8" OD (BLUE)

So, the drain tube attached to that tee is supposed to be an 18-inch long piece of 1/2-inch flex tubing, approximately 5/8-inch outside diameter and supposedly blue. If it's there and meets those specs is up to you to figure out. Perhaps Winnebago meant for the drain tube to be dropped through the 3-inch sewer pipe opening for draining, then tucked back into the wet bay when done. That would keep the drain from sticking down through the wet bay floor and getting hit or clogged with who-knows-what. If the tube is sitting on the floor of the wet bay now, opening the valve(s) (with an air vent open, too) will spill water-plus-antifreeze onto the wet bay floor.

As far as the path for your tank fill water, it is correct as you have drawn in blue.

 

[S.Rodimus]

Sounds like any one of those pipes above may be frozen. Getting to the spot is likely going to be tough.
But there should be a drain sticking down from the center connection if it is as shown???

What happens when you open those two white valves? I would expect water to come out the bottom.
But to find the leak, the side will have to be taken apart to get to the pipes above. OR there are times when pulling the inside wall off is better?

Nothing ever froze, and there are no leaks.

 

[S.Rodimus]

S.R.-

Tee "T-22" is in your first photo, between the two drain valves. Whatever comes out the drains when the valves are open goes through that tee and then exits the tee out the leg that's almost out of view, pointing towards the passenger side of the coach. On the diagram this is drain tube "TU-8." According to the Water Parts Identification List (link here):

T-22: 000156326 / 326721-01-000 TEE 1/2" PEX X 1/2" PEX X 1/2" MPT
A-15: 123152-01-000 ADAPTER-SWIVEL 1/2" FPT X 1/2" BARB
TU-8: 112176-01-000 TUBING-FLEX X 1/2" ID, 5/8" OD (BLUE)

So, the drain tube attached to that tee is supposed to be an 18-inch long piece of 1/2-inch flex tubing, approximately 5/8-inch outside diameter and supposedly blue. If it's there and meets those specs is up to you to figure out. Perhaps Winnebago meant for the drain tube to be dropped through the 3-inch sewer pipe opening for draining, then tucked back into the wet bay when done. That would keep the drain from sticking down through the wet bay floor and getting hit or clogged with who-knows-what. If the tube is sitting on the floor of the wet bay now, opening the valve(s) (with an air vent open, too) will spill water-plus-antifreeze onto the wet bay floor.

As far as the path for your tank fill water, it is correct as you have drawn in blue.

This is all extremely helpful, l1v3fr33ord1. Thank you! I think the tube may just be gone, given how old the rig is. I'll look at it all again tonight when I get home, armed with all this new knowledge you've shared, to see if it's just been stuffed in one direction or another. Either way, I think we've got this all figured out now.