Community Forums

saboga · 10-23-2017, 11:17 AM

OK, we can't figure out how this happened, but evidently it's the second time.

Yesterday, we had about 1/2 tank of fresh water, and the black water tank was only 1/4 or so full. We went to bed last night, and this morning, noticed that the hand sink in the bathroom was almost full of water. When we flushed the toilet, pressurized black water shot up out of the toilet!!

Then we noticed the fresh water tank was empty. So, all we can figure is that somehow. the water from the fresh water tank got into the black water tank without going through the toilet flush process.

With the water backed up in the hand sink, it seems the hand sink drains into the black water tank, not the grey water like one would expect. And that would seem to be the only other way for water to get into the black water tank.

We were totally disconnected from all hook-ups last night, and we did not hear the water pressure pump run at all during the night. So, does anyone have any other ideas what might have happened?

We have been camping the last month on the Blue Ridge Parkway, mostly totally without hookups, and this is the first issue we have had.

JPO1980 · 10-23-2017, 11:35 AM

I had a previous mh that drained hand sink into black tank, probably because of locations it was easier/cheaper to plumb that way. As for how the water left the fresh water tank, I would presume faucet not fully closed and pump was on. If not, you have a mystery. Good luck

grtharris · 10-23-2017, 07:30 PM

saboga, what is year and model of your motorhome? Please add it to your signature.

AFChap · 10-24-2017, 07:20 AM

It had to enter through the toilet or hand sink via the pump. The pump noise maintaining pressure would be very low and not very noticeable. Winnebago drains the vanity sunk to the black tank to "help" you ensure you have sufficient liquid there to avoid a sludge backup.

AKIQPilot · 10-24-2017, 01:56 PM

Quote:

Originally Posted by AFChap

It had to enter through the toilet or hand sink via the pump. The pump noise maintaining pressure would be very low and not very noticeable. Winnebago drains the vanity sunk to the black tank to "help" you ensure you have sufficient liquid there to avoid a sludge backup.

I did not realize this. Sounds reasonable though. I will look at mine a little closer to see where the vanity sink drains.

Thanks for the heads up.

Old-Biscuit · 10-24-2017, 02:03 PM

Three ways water goes to black water tank

Toilet...
Bathroom sink
Tank Flush Connection

From fresh water tank.......pump and then either bathroom sink dripples all night long and/or toilet water valve leaks thru and bowl seal also leaks

saboga · 10-24-2017, 02:26 PM

It must have been the vanity sink running all night that did it. So now we will be careful to turn off the pressure pump at night just in case. Since the water tank ran dry, there is no way to know for sure if it was still partially open or not.

But that brings up the issue: if we had been connected to the city-water hose hook up and there had been an unlimited supply of water, we would have awakened to a flooded RV!

There is a rule in the boating and marina world that says never to leave a hose connected and in the on position. Always fill your tank and then turn it off and disconnect it. All it takes is a broken hose or a loose fitting and you can sink your boat. Fortunately RV's won't sink, but water damage can sure ruin the floors and cabinetry!

Thanks for all the input!

Tom-NC · 10-28-2017, 12:26 PM

Hi,
Sorry to hear of your problem however I don't think your vanity sink goes into the black tank. You can easily check by looking at the plumbing diagram for your coach at the WBGO site. I do believe though that you left the vanity faucet open a little causing the sink to fill up with the water pump on. You neglected to say what was in the sink, was in black water stuff or just water. You also neglected to say how full was the black tank.
Lastly I would say to contact WBGO and ask the techs their thoughts.

Old-Biscuit · 10-28-2017, 12:56 PM

Quote:

Originally Posted by Tom-NC

Hi,
Sorry to hear of your problem however I don't think your vanity sink goes into the black tank. You can easily check by looking at the plumbing diagram for your coach at the WBGO site. I do believe though that you left the vanity faucet open a little causing the sink to fill up with the water pump on. You neglected to say what was in the sink, was in black water stuff or just water. You also neglected to say how full was the black tank.
Lastly I would say to contact WBGO and ask the techs their thoughts.

This is what OP stated in first post

Yesterday, we had about 1/2 tank of fresh water, and the black water tank was only 1/4 or so full. We went to bed last night, and this morning, noticed that the hand sink in the bathroom was almost full of water. When we flushed the toilet, pressurized black water shot up out of the toilet!!

Then we noticed the fresh water tank was empty.

Fresh water tank....1/2 full
Black tank.............1/4 full

Next morning
Black Tank FULL---so full toilet BURPED at them when flushing
Fresh water tank EMPTY
Vanity sink FULL

Sounds like fresh water got transferred to black tank during the night.
Vanity faucet running likely suspect.

Plumbing diagram shows all sinks and shower draining into grey but black tank had an increase in level, fresh water tank decreased in level and vanity sink was full.

So plumbing diagram wasn't followed......????

Course one only needs to drain black tank then turn vanity faucet ON and watch water flow out black tank drain to confirm it DOES drain to black tank

If it doesn't -----Ghostbusters would be next step

jdyson · 10-28-2017, 05:50 PM

I really am suspecting a plumbing error, wherein the vanity sink got tied into the wrong T-x connector (wbo plumbing diagram-speak) and is therefore draining into the black tank, but who knows for sure until you drain grey/black tanks, hook up to city water, turn on vanity and monitor levels to see which tank fills. Low-tech solution, but it will at least reveal 'what'. Then you can move on to 'why'. Good luck...

Podivin · 10-28-2017, 06:03 PM

It's not at all uncommon for a vanity to drain into the black tank.

And I believe Old Biscuit came up with the easiest way to test to see where the water goes. Go to a dump station, dump the black tank, leave the hose connected and, turn on the vanity faucet and see if water flows out the dump hose.

awol50 · 10-28-2017, 11:22 PM

Quote:

Originally Posted by Podivin

It's not at all uncommon for a vanity to drain into the black tank.

And I believe Old Biscuit came up with the easiest way to test to see where the water goes. Go to a dump station, dump the black tank, leave the hose connected and, turn on the vanity faucet and see if water flows out the dump hose.

Sounds like a plan. Actually I wouldn't mind if my bath sink drained into black water tank. When I don't have sewer hookup my grey water tank fills much faster from the shower and kitchen.

Arizona · 10-29-2017, 07:36 AM

All three of our Winnebagos have had the bathroom sink drain to the black water tank. We limit our hand washing to the kitchen sink while dry camping so it doesn’t fill as fast. Someone must have left open the faucet.
Pretty crappy morning.