Why can't I fill black tank with tank rinse on the hose?

[scottandanna]

I am trying to fill up my black tank with fresh clean water, and run it out, but when I put the hose on outside, I can see the tank fill up to 2/3 pretty quickly, then it seems to stop filling.

Is there a safety switch in there to prevent it from accidentally overflowing while on the hose?

When looking down into the toilet, I can see lots of motion and water sloshing, then it sorta just calms down when it hits 2/3 full.

If there is a safety valve, that is a pretty cool deal, and I am glad to know it is on there.

[MSHappyCampers]

The vent is a pipe out the top of the RV! It sounds like that is stopped up so air is being trapped in the top of the tank preventing it from filling with liquid!

[Scatterbrain]

Originally Posted by MSHappyCampers

The vent is a pipe out the top of the RV! It sounds like that is stopped up so air is being trapped in the top of the tank preventing it from filling with liquid!

Not if you can look into the tank from the toilet.

[scottandanna]

I have the fan on and the bathroom vent open, while looking down into the toilet.

Also, now that I have found a major leak under my bathroom sink and fixed it, I noticed that there is some valve up under the sink in-line with that black-tank cleanout hose, and it is slowly dripping, too. What is that, and why is it dripping?

Luckily, not dripping as bad as the other leak I fixed. But still, I flushed the tank twice and this thing dripped 5 or 6 big drops under the sink.

[Bigd9]

I making a few guesses here. When you say "but when I put the hose on outside, I can see the tank fill up to 2/3 pretty quickly, then it seems to stop filling. " your are talking about the tank flush? If so, your tank could be like mine. There is a wide upper tank area, then the tank steps down, then it steps down again where the outlet valve is located. On mine, if I dump a gallon of water in it, the 1/4 full lights come on!, Then the 1/2 light comes on after a short while, but at that point it takes a long time to fill the tank up all the way. I've learned to live with it,

On your second question, if that black plastic thingy is actually on the flush water line, then it could be a one way valve to keep black tank water from entering the fresh water system.

[Old-Biscuit]

Picture is of the black tank flush system 'anti-siphon vacuum breaker' device that stops water from backflowing from an OVERFILLED black waste tank into the water supply.

They stop any siphoning action by opening to atmosphere when water supply pressure is shut off........

BUT they can/do fail and leak water out of 'opening' inside the RV
Luckily yours is just dripping.
Others have found it due to flooding

And WHY do you need to FILL your black tank????
That can over-pressurize tank when vent line goes under water
Over-pressurizing can cause tank to sag....or even fail at seams/corners
Overfilling can cause water to come up out of toilet
Overfilling can cause water to go up the full length of vent line and spew poop water on/off of roof

Usually there is a 'label/sticker' that warns about using flush system with drain valve OPEN because there is NOTHING to prevent over filling.......water will continue to go in until water supply is secured.

[twogypsies]

Wow! You're sure getting off to a bad start of your trip with the leaks, etc.

If you'd just get out of town I'm sure things will be much better for you.

[scottandanna]

Originally Posted by twogypsies

Wow! You're sure getting off to a bad start of your trip with the leaks, etc.

If you'd just get out of town I'm sure things will be much better for you.

What happened was we kept the trailer under a hay shed for the past year, so it never got exposed to any severe weather. Except for a week at Thanksgiving, a week at Christmas, and two weeks in the summer, where we DID experience severe weather, but no leaks.

Now that it has been in the weather, and trust me, if you have been watching the news, it has been HORRIBLE down here these past couple of weeks. Anyway, finding a couple of minor leaks, fixing them before we hit the road.

I agree, though...when we get away from the coast and into moderate weather areas, we will not have any more leak issues.

As for the tank, I moved the trailer today, and it has had an empty tank for over a month, and all of a sudden it says 3/4 full when I look down and can see the bottom. So I figured, since there is no #1 or #2 in the tank, this is a good time to wash it out again, one last time before it is full of 1 and 2. So I tried to fill it up and flush it out while I had the chance.

As mentioned above, I wonder if our tank is also like yours, where it fills up quickly to 1/2 or 2/3, then takes a BUNCH more to fill it up.

Anyway, I dumped some dish soap down there, filled it as much as I could, drained it, and nothing coming out but soapy water, and gauge now reads EMPTY, which is what I wanted.

[scottandanna]

We had 3" in the rain gauge yesterday, and dumped it. Then another 4" in it today!!!

That major leak at the shore power socket stayed dry all day. So that major leak is fixed.

The few drops coming from this valve would dry up in an hour, especially when we get away from the humid coastal area. But still, would like to have NO leaks in the end.

[mojoracing]

Your tank is stepped and that is why it fills up fast at first. When you look down the toilet you see turbulence while it is filling at first. When the water level covers up the flush sprayer, you see less turbulence but it is still filling. DO NOT over fill your tank. Do not fill your tank using the tank rinse. If you want to clean it, put a few gallons of water in with some dish soap and let it slosh around while driving. If you want a clean tank, use plenty of water while flushing and dont dump the tank until it is 3/4 full. After dumping, use your tank rinse for 5 minutes with the dump valve open and you will have a clean tank. As long as your sensors are working, your tank is clean enough. I have seen folks fill their tank using the rinse and they walk away and forget it and a few minutes later it is spraying out the roof vent or worse, flooding the inside of their coach with black tank contents.

[BBQ Warren]

I don't know what is going on with your but the leak sounds similar to what I experienced. We had a leak under our bathroom sink and we discovered it only happened when we were flushing the tank. It is a check valve and we removed it and saw it was cracked. I forget the name of the company but it was on the part. I googled the company and they were super. They sent me a new valve at no cost. We found out the cause of the problem. We do an excellent job of winterizing but we never thought to put some antifreeze in the black flush. So it ended up cracking the valve. Easy to replace.


2014 Keystone Outback Tavel Trailer
2012 Ram 1500
Retired Navy

[Bigd9]

Originally Posted by BBQ Warren

I don't know what is going on with your but the leak sounds similar to what I experienced. We had a leak under our bathroom sink and we discovered it only happened when we were flushing the tank. It is a check valve and we removed it and saw it was cracked. I forget the name of the company but it was on the part. I googled the company and they were super. They sent me a new valve at no cost. We found out the cause of the problem. We do an excellent job of winterizing but we never thought to put some antifreeze in the black flush. So it ended up cracking the valve. Easy to replace.


2014 Keystone Outback Tavel Trailer
2012 Ram 1500
Retired Navy

I have never winterized that black tank flush line, just never thought about it! I will start doing it now that you mentioned it. Thanks

[scottandanna]

I will get up under there and check out that valve. Thanks for the heads-up

[BBQ Warren]

Originally Posted by scottandanna

I will get up under there and check out that valve. Thanks for the heads-up

If you don't see water on the floor, you are probably good to go. BTW I like your avatar picture. I'm a huge boxer fan.