Grey water drainage backup question

[katidesc13]

I tried searching this forum for a similar post, but for whatever reason, the advanced search filters seemed to be a little relaxed about sticking to criteria today.

I have a 1998 Scamp 13' with a grey water outlet port that hooks to a garden hose. My problem is that it keeps backing up or vapor locking where I have to wiggle the hose outside every time to make it drain. My RV site manager purchased an adapter to connect the garden hose to the larger RV dump ports, but it still backs up. It's becoming VERY frustrating and hardly worth the hassle.

Does anyone have suggestions or recommendations on how to set this thing up to ease the drainage process? I don't have a bathroom or toilet, so the only grey water out is from the sink.

Thanks in advance!!

Katie

[mszabo]

You need to build a venturi. Think of a pop bottle turned upside down.
It's hard to empty.
You can make one out of pvc fittings. Looks like the fitting you use to fill waterbeds.
Do don't have time tonight to post a picture but, I will tomorrow.

[Steve Hammel]

If you are sure that nothing is impeding the water from flowing then you need to rig up some type of a vent. Without a vent the water flows so fast that the air in your drain line can't get out of the way fast enough causing the water to back up. You will notice that RV's, and homes for that matter, that have "permanent" plumbing installed always have a line that runs to the roof for the air to escape. Obviously that is probably not an option for you so you may need to find an under counter vent at your local Lowes, Home Depot, etc. These are small vents that just let the air escape so the grey water can run without having to push the air out of the way.

[Eddie Longest]

First I would make sure your drain hose under the sink is not kinked or the trap is stopped up. There may be grease, crud or trash build up at the barb inside the hose wall connector. I would try sticking a wire in the drain hole and wiggle it around while running warm water through the drain with a bucket on the ground. The plastic wall fittings and drain trap get brittle and can easily break off so be careful.
Warning:
Wear your PPE.
Do not use hot water or you may burn yourself.
Ensure someone is around so if you fall in your bucket you won't drown.
The drain plug could be a choking hazard.
Make sure you are in a well lighted and ventilated area.
I can not be held responsible. I am not giving advice, these actions that I may take.

[Steve Hammel]

Another thing to look at is the diameter of the drain hose. Get the largest diameter hose you can find. I might even try buying large diameter bulk tubing and put a hose fitting on the end.

[katidesc13]

With the advice from you lovely people, google, and a bit of brainstorming at my local hardware store, it's fixed!! It merely needed an air vent. Now it's running smoothly and I'm stoked!! I'm getting a little better at this full timing thing!! Thanks everyone!!


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[Steve Hammel]

Very creative!!!!! Glad it's working fine.

[Bob Miller]

Not to throw gray water on your party, but that drain fitting is not designed to hold the weight and leverage of your air vent and, if someone doesn't first run into it and break it off, it will break off on it's own.

And, if you get an obstruction in the drain hose, it will spill your gray water on the ground because the open end is below the level; of the sink drain. Not a good thing (as Martha might say!)

You can get a standard "air-gap" vent and put that inside and you won't risk damage to your outside fitting. Or just a "T" fitting and a short length of tubing under the sink can take care of it as well. Just be sure that the open end of the tubing is at or above sink level.

[Eddie Longest]

Good post for info. I thought you were using a short piece of hose going into an open container. In your case with a long hose you will need a vent if you have a trap under your sink drain. On some older trailers traps were not installed and the inside drain hose connected a straight tail piece below the sink. In that case no extra vent should be needed.
Eddie

[katidesc13]

Does someone have a picture of what they're talking about as far as what it should look like under the sink? I'm concerned about the weight and torque of my makeshift vent on the attachment, and as someone kindly pointed out, because it's below the level of the sink it will spill out if the drain backs up.

Here's a picture of the connection below the sink.

That clear tubing runs straight to the drain outlet. Is that white section the "trap" that you're referring to?

I'd love to have a more permanent and appropriate fix, but I have no point of reference with most of this stuff and therefore have no idea what I'm actually looking for!

Thanks for all the help!!


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[Eddie Longest]

The white thing under the sink is the trap and what you have looks OK. On your outside contraption how about re plumbing it to be less stressful on the connection. Turn the T around connect the single side to the trailer, point the hose connection to the ground and extend your vent tube up to the belly band and figure a way to temp. attach it to the trailer. If it is all done in white PVC it should not be too noticeable. They also make a vacuum breakers for household sinks but they also have to be above the drain. I think turning the T around will really help if you don't have elevation issues.
Eddie

[Byron Kinnaman]

I had the same thing happen to me recently. There was some gunk build up in the trap. I cleaned it out with a piece of wire and all is well. I did buy a replacement trap to put in the spare parts locker.

[katidesc13]

Originally Posted by Eddie Longest

The white thing under the sink is the trap and what you have looks OK. On your outside contraption how about re plumbing it to be less stressful on the connection. Turn the T around connect the single side to the trailer, point the hose connection to the ground and extend your vent tube up to the belly band and figure a way to temp. attach it to the trailer. If it is all done in white PVC it should not be too noticeable. They also make a vacuum breakers for household sinks but they also have to be above the drain. I think turning the T around will really help if you don't have elevation issues.
Eddie

Thanks Eddie for the feedback! I reworked the setup to try and minimize the torque as best I could. The connection that hooks directly to the output valve rotates so there shouldn't be any rotational torque on it but there will still be vertical torque. I may even try to attach this contraption to the distal end of the drain system where the hose hooks to the large diameter RV drain and simply apply a tall enough piece of PVC to be above the belly band of the trailer.


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[katidesc13]

Here's a pic of the distal end with the adapter


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[Carol H]

Katie, I think Byron has the best suggestion, not sure you really need all that for venting...... may simple be a build up of gunk in the trap. Helped a friend replace the trap last year and it was jammed full of gunk.. nothing wrong it just needed a good clean out and the kink taken out of the drain hose attached to it.

[katidesc13]

Originally Posted by Carol H

Katie, I think Byron has the best suggestion, not sure you really need all that for venting...... may simple be a build up of gunk in the trap. Helped a friend replace the trap last year and it was jammed full of gunk.. nothing wrong it just needed a good clean out and the kink taken out of the drain hose attached to it.

Am I wrong in thinking if it were a drain trap problem that I'd still continue to have problems with it backing up (because the vent is distal to the trap)? Since allowing the air escape, I haven't had any problem with the drain at all. I figured the backup was mainly because I've attached a hose to the RV connection and created a long, small-diameter, closed circuit and therefore significantly increased the peripheral resistance. It didn't do this when I was emptying it directly into a buck using a short length of hose.

(20 minutes after writing above paragraph): For good measure (and piece of mind), I removed the drain trap to inspect for build-up and it was completely clear. I think the problem was my original suspicion about the air needing venting. I'm sure I'll tweak my system a couple more times before finding the perfect solution, but for now it's working really well!

Thanks for all the feedback!

[Byron Kinnaman]

Originally Posted by katidesc13

Am I wrong in thinking if it were a drain trap problem that I'd still continue to have problems with it backing up (because the vent is distal to the trap)? Since allowing the air escape, I haven't had any problem with the drain at all. I figured the backup was mainly because I've attached a hose to the RV connection and created a long, small-diameter, closed circuit and therefore significantly increased the peripheral resistance. It didn't do this when I was emptying it directly into a buck using a short length of hose.

(20 minutes after writing above paragraph): For good measure (and piece of mind), I removed the drain trap to inspect for build-up and it was completely clear. I think the problem was my original suspicion about the air needing venting. I'm sure I'll tweak my system a couple more times before finding the perfect solution, but for now it's working really well!

Thanks for all the feedback!

If it's working and you're happy with it, I wouldn't fuss with it. I related my experiences, but that doesn't mean it would be the same for everybody. I hope you're enjoying living in your Scamp.

[stevebaz]

Just remember what you have now is an open vent to the sewer right by your side windows. When the drain isn't flowing gases can escape up the line. If it becomes a problem get a couple of sections of pvc and glue a coupler on one end then you can just slip them together and extend the existing vent above your windows. You don't have to glue it up solid.

[mszabo]

Great job Katie, I was going to post my picture sooner but, you had it made ASAP.