Please Help Identifying These Water Lines

[BigSky!]

We recently purchased a 2015 Keystone Cougar Travel Trailer. We've taken it out a few times and I've become quite familiar with it. However, there's one thing (currently) that I can't identify. In the picture below you will see two drain lines. One red, presumably hot, and one blue, presumably cold. What do they drain. I opened both after our most recent five-day outing and only a few ounces of pink RV anti-freeze flowed out and nothing else. They are located, roughly, below the location of the shower in the bathroom. I can see no place inside, that is accessible, where there would be a bypass valve of any sort. I'm stumped. The single one you see in the background is the fresh-water tank drain.
https://i.imgur.com/RVBJ3SW.jpg

[sourdough]

Those are the low point drains for hot (red) and cold (blue) water lines.

[Bill-2020]

They are low point drains for hot and cold water lines. Bypass valve would be near the water heater.

Welcome, by the way. :wave:

[chuckster57]

As Danny said, they are the low point drains. They will allow all the water in the fresh water system to drain out by gravity as long as you open all the faucets. It WILL Not drain the fresh water tank. The fresh tank will have its own drain.

[Bill-2020]

They are low point drains for hot and cold water lines. Bypass valve would be near the water heater.

Welcome, by the way. :wave:

Two minutes too late - Danny types fast than i do. HAHAHA!

[BigSky!]

Those are the low point drains for hot (red) and cold (blue) water lines.
That is what I assumed; but, what do they drain? I don't mean to sound obtuse; but, we had just returned from camping and using every plumbing fixture in the camper and I decided to open them, assuming they would drain all of the water remaining in the lines. Nothing other than the aforementioned few ounces of antifreeze came out. I would assume that they would drain all of the hot and cold lines that had water in them. However, I just had a little tiny bit of antifreeze.

[travelin texans]

That is what I assumed; but, what do they drain? I don't mean to sound obtuse; but, we had just returned from camping and using every plumbing fixture in the camper and I decided to open them, assuming they would drain all of the water remaining in the lines. Nothing other than the aforementioned few ounces of antifreeze came out. I would assume that they would drain all of the hot and cold lines that had water in them. However, I just had a little tiny bit of antifreeze.

Unless you opened faucets inside they wouldn't do anything but dribble a second. Open all the hot/cold faucets then open the low point drains.

[chuckster57]

Unless you opened faucets inside they wouldn't do anything but dribble a second. Open all the hot/cold faucets then open the low point drains.

I guess nobody read my response? :whistling:

[flybouy]

The antifreeze was most likely what was setting in the section of pipe from the pipe connection to the cap. It won't drain out rapidly unless all the faucets are opened to let air in. To see how it works stick a straw in a glass of liquid. Place your finger over the open straw and pull the straw out of the glass. The liquid will stay in the straw until you remove your finger and allow air to replace the liquid.

[Gegrad]

Weirdly enough, very little comes out of my cold line drain unless I have a faucet on and the hot water heater drain plug removed. If I open my lines and just turn on a faucet or two it will drain a little (more than what OP had, but not a complete drain), but if I drain the HW tank at the same time it will drain gallons. Does not make any sense, I know.

[BigSky!]

Thank you all for the input. My previous trailers never had these. So I get it now and I appreciate all of the responses. I suppose this will aid in my winterization.

[flybouy]

Weirdly enough, very little comes out of my cold line drain unless I have a faucet on and the hot water heater drain plug removed. If I open my lines and just turn on a faucet or two it will drain a little (more than what OP had, but not a complete drain), but if I drain the HW tank at the same time it will drain gallons. Does not make any sense, I know.

Larger hole, more air. If you've ever taken out the faucet screens to clean them they typically have a disc with a small hole for the water to come out before hitting the aerator. Some call it a "water saver". Opening the tub and outdoor shower faucets will drain it quicker also. I open all faucets, uncap the drains and apply about 15 psi of air pressure when I winterize. That speeds things up.

[CrazyCain]

I guess nobody read my response? :whistling:

:lol::lol::lol::lol:

[flybouy]

I guess nobody read my response? :whistling:

OP came back in question #6 so apparently he didn't understand.

[chuckster57]

It’s all good!! As long as the OP got his answer.

[Gegrad]

Larger hole, more air. If you've ever taken out the faucet screens to clean them they typically have a disc with a small hole for the water to come out before hitting the aerator. Some call it a "water saver". Opening the tub and outdoor shower faucets will drain it quicker also. I open all faucets, uncap the drains and apply about 15 psi of air pressure when I winterize. That speeds things up.

Ah, ok, that makes sense. I was thinking about it from a "HW heater open helps the cold system drain?" angle, but that explains it.

[JRTJH]

Weirdly enough, very little comes out of my cold line drain unless I have a faucet on and the hot water heater drain plug removed. If I open my lines and just turn on a faucet or two it will drain a little (more than what OP had, but not a complete drain), but if I drain the HW tank at the same time it will drain gallons. Does not make any sense, I know.

Just curious, but have you tried opening the pressure relief valve to see if it does the same thing as removing the anode rod? Seems like either "should" relieve the vacuum and allow the low point drains to flow...