What's the purpose of this black tank fitting?

[Nevadastars]

We just picked up our Tioga 31w and organizing everything on it. I found this black tank cap with a hose end on it. The fitting has a ball valve on it to shut of the water flow. We have had two other RV's and never used anything like this before. Can someone explain what it is for? Seems odd to have a hose fill from the bottom of the black tank, especially since ours dumps straight down. Here is a pic.....

[dieharder]

I'd hate to use that to back flush... a whole bunch of "stuff" would get in between this and the pull valve, you'll get a bath of it switching this to your slinky. Chunks that might be leftover in the tank might not pass through the hose on this attachment...

[2oldman]

That's what I get for thinking.

[JaxDad]

2oldman wrote:

JaxDad wrote:
Think it through...Where do you suppose all that 'clean' black water trapped between the valve and cap goes when you remove it to put the stinky slinky back on to drain the back wash water? Yup, it ends up on you and the ground your standing (kneeling?) on.

I did think it through. Apparently you haven't read, or you disagree with, my explanation of how that doesn't have to happen. It's on page 2.

No, I read it. I prefer to keep my feet, and site, dry and clean.

Funny that the manufacturers and sellers of them though call it a grey water drain cap. They're just not as smart as some people I guess.

[ol_Bombero-JC]

Chris Bryant wrote:


Also rigs with 2 outlets- (like rear kitchen fivers) can use a garden hose for the second outlet.

Have one of those (5th).

The three tanks = black, grey and kitchen/grey.

The kitchen grey tank has a standard 3" drain outlet connection.
I use a ball valve on the garden hose connection of the 3" cap.

The drain hose is a garden hose with female connections at each end. Connects to the (male) garden hose connection on the 3" sewer elbow.

The *way too short* for the above - "washer hose" (w/ double female) is (as already posted) most likely a drain to/for a grey water tote.

~

BTW - The siphon "technique" would make a great YouTube video!!..:C

~

[2oldman]

JaxDad wrote:
Think it through...Where do you suppose all that 'clean' black water trapped between the valve and cap goes when you remove it to put the stinky slinky back on to drain the back wash water? Yup, it ends up on you and the ground your standing (kneeling?) on.

I did think it through. Apparently you haven't read, or you disagree with, my explanation of how that doesn't have to happen. It's on page 2.

[Chris_Bryant]

It's a grey water drain hookup. Many campgrounds *used* to have dry wells for grey water, some still do. Also rigs with 2 outlets- (like rear kitchen fivers) can use a garden hose for the second outlet.

[JaxDad]

Nevadastars wrote:

JaxDad wrote:


I'm pretty sure the only possibility is grey water drain.

Like I stated above, the ball valve opening on the hose fitting is pretty small, so it would drain very slowly. I cannot see any purpose in an auxiliary grey tank drain when the grey valve works just fine as is.

Think it through, you have that cap in place, the hose connected and the water on with the black valve open. You turn the little ball valve and start back washing the black tank. When you've back washed it sufficiently you turn off the ball valve and close the black valve.

Where do you suppose all that 'clean' black water trapped between the valve and cap goes when you remove it to put the stinky slinky back on to drain the back wash water? Yup, it ends up on you and the ground your standing (kneeling?) on.



On the other hand, the folks that make those caps, and the folks that sell them (see link below) describe them as "Attach a garden hose to the 3/4" fitting to drain grey water tank.".

Clickey-Clickey .

[austinjenna]

We bought one when the CG we stayed at let you drain your gray tank into a small sewer at your site, the sewer was not big enough for your sewer hose. Everyone at the CG had them, they sell them at walmart

[2oldman]

JJBIRISH wrote:
…with the valve close to the blue boy there is little chance of over filling…

I can't argue with that.. makes sense. I always have to be careful to allow for what's in the drain pipe.

[Bucky_Badger]

ScottG wrote:
Could be to connect to a macerator pump.

No, they use the 3 inch pipe

[JJBIRISH]

the only reason I see for the valve is the blue boy is smaller than the gray tank and shutting off the gray tank valve could allow the blue boy to overfill before draining everything held in the pipe and hose after the gate valve is closed…
with the valve close to the blue boy there is little chance of over filling…

The reason for using the double female hose is because the cap for the trailer and the blue boy cap as well as the blue boy vent all have male connectors, and the washer hose comes made up that way already…

we can agree, that to some extent, it's possible to use it as both… although possible is a pretty wide take when compared to the probabilities and that some new totes I believe come with these things less the hose valve as included accessories, but I could be wrong about that...

[JJBIRISH]

2oldman wrote:
Maybe we can just all agree, that to some extent, it's possible to use it as both.

hey I thought it was my turn, but I wasn’t aware it was a competition… 🙂

[RV-1_2n-FUN]

JaxDad wrote:
........

I'm not so sure, the 'hose' is actually one half of a pair used as supply lines for a washing machine, double female. The shut off is a common inline male / female stubby fitting used on a garden hose.

I think the fact it ends female is purel a result of the double female hose, had it been a conventional hose (one male, one female) it would have terminated in a male fitting.

It would be useless as a back flush tool since there's no way to drain the water without removing the cap and pouring everything from the gate valve out on the ground.

For back flush you'd need something like this;



I'm pretty sure the only possibility is grey water drain.

Look at the picture and you will see 4 wings to grab on to the dump outlet. If one wants to back flush, one best make sure there are 4 wings not 2 so a more secure fit is provided. One broken wing out of 2 can cause a mess coming from a black tank.

I will agree with those suggesting that it is a simple gray water trickle hose either for emptying on the ground or slowly into a tote tank.

[wa8yxm]

That is not a black tank fitting but it could be used to back flush,, Would be messy, but it could be done.

On my coach there are three tanks ,< Black and gray, plumbed like you expect with a single 3" outlet, and a "Wash" tank that is rather distant and has it's own 3" outlet.

I use the adapter you pictured to drain it, via a 3/4 inch GRAY garden hose..

Back to the hole in the ground.. The 3" elbow has a male hose fitting molded in,, the fitting is blocked but I drilled it out,, that's where the other end of the hose hooks up.

You need a female-famale connector too (Your washing machine hose works well) mine is located at the adapt-a-cap,, Same as in your photo.