Black Water Tank Flush

Finhawk · 05-06-2016, 11:37 AM

My Flush has stopped has stopped working. I hooked the water to it and there is no sound like it normally makes and hardly any water gets into the tank. Is there a filter in that system that might get clogged?

Lanny1763 · 05-06-2016, 06:31 PM

This may sound crazy, but when not flushing my black tank down south in Lower Alabama, I'd leave my flush hose laying on the ground. One day I connected it to the flush inlet and got no whoosh of water going in like normal to the black tank. Turned off water and disconnected the hose to find that a small frog had crawled into the hose and was blocking the water flow into the inlet for the flush. Poor little guy didn't make it, but once cleared the hose was back to normal. Always expect the unexpected!

Keith K · 05-06-2016, 09:03 PM

Is it completely clogged, by that I mean do you have any water running through the sewer hose? I've had occasions where I couldn't hear the sound, but the tank was filling. After a few more flushes, the sound would return. If it's still filling the tank but without making the spray sound, next time you travel fill the tank at least 3/4 and add a bag of ice. That should help. As a last resort, on a previous motorhome, I removed the spray head to find that the holes were very small and easy to clog. I drilled them out a bit and it worked great afterward.

SuperGewl · 05-10-2016, 10:49 PM

Yes to help with the cleaning of the Black tank and the Black tank Wash system. Fill the tank about 1/2 to 3/4 full of water, also add some Bath Salts (Dollar Store) to the mix with a teaspoon of dish washing liquid. You can put some ice in the mix also, about 5 to 10 lbs. Then when you get to your next stop dumper, dumper good. Also hook up the Black tank wash and run it. This should have broken up any hard deposits on the side walls and in the wash nozzles. Rinse and repeat as necessary.

Finhawk · 05-13-2016, 02:22 PM

I've checked externally for obstructions. In fact that was the first thing I did. The hose is clear, nothing that I can see in the pipe. The tank empties just fine. the problem is that no water is getting to the flush system inside the holding tank. No noise from the sprayer, no water going into the tank.

grtharris · 05-13-2016, 05:21 PM

Finhawk If you can see the valve under the bathroom vanity on the left side behind the draws give it a couple of good wacks. High water pressure can cause the valve to stick.
When I lived in the city I had to use a valve to control the water flow into the flush to keep it from locking up.

oldcat · 05-13-2016, 05:46 PM

What grtharris said. It is not uncommon to have that check valve fail. If "wacking" it doesn't work, a replacement valve is around $10. Over the years I have had it happen to me twice. I now carry a spare valve in my parts box.

Safe travels.

Finhawk · 05-21-2016, 07:24 PM

Quote:

Originally Posted by grtharris

Finhawk If you can see the valve under the bathroom vanity on the left side behind the draws give it a couple of good wacks. High water pressure can cause the valve to stick.
When I lived in the city I had to use a valve to control the water flow into the flush to keep it from locking up.

I checked the cabinet. My problem is that it has a back that is enclosed. All I can see is a painted back wall. . Maybe a saws-all but then I don't know how much room there is between the cabinet and the pipes. That could lead to problems that I don't even want to think about.

Finhawk · 05-25-2016, 12:56 AM

In my rig, that check valve is in the bedroom wall, not behind the cabinet. One mystery solved. Now to change out the valve. Thanks for the help, folks

blang · 05-25-2016, 07:27 AM

I recently experienced the same occurance... no water would pass through the flush. I determined it had been some time since I flushed and, quite possibly, the tank had become over-filled and allowed... um... matter to enter the flush nozzles and solidify.

I bought a twist-on valve like Valterra T58 Twist On Waste Valve, 3" so that I could utilize a full grey tank to fill the black tank at will (my grey fills up before the black with dish and clothing washers). Of course, if you are more of a full hook-up guy than I am, you can disregard the valve and just use your city water.

Anyway... back to the point. I dumped about a third of a box of calgon, borax, whatever you have in the way of water softener and also a cup or two of Dawn in my 75 gallon black tank and filled up what I guessed to be about 60 or 70% full. Plenty of room for sloshing and also not wanting to be spewing suds out the vent on the roof as I went down the road. At the end of the trip, hooked up the hose to the flush and, after sputtering some, it began to run like it used to. So I dumped my tank and continued flushing.

I'm thinking, at some point, the tank was over-filled and allowed stuff to solidify in the flush spigot and the softener & soap loosened it up enough to work again. In the future, I'll be running the flush more often.

Just for those who might say a check valve would prevent this from happening... my check valve is actually right at the hose connection so how ever long that internal hose is would certainly be room enough for matter to get in and solidify.

Happy flushing!

Finhawk · 05-27-2016, 06:47 PM

Well, it was not the check valve. Now I think it's a buildup of the crud in the Las Vegas water. So the plot thickens. No pun intended

Rendon · 05-20-2018, 12:46 PM

Can you please tell me where the spray head is located on your MH? I have a 2004 Itasca Sunrise with a clogged back flush and I'm pretty sure its where the line goes into the black tank but I can't seem to see where that is. Its driving me nuts!

Peggy

luvlabs · 05-21-2018, 10:11 AM

Is this a San-T-Flush? If no water is coming through, you are going to have to remove the spray head from the black tank, clean the dried crud off of it, and enlarge the holes slightly to prevent this from happening again.

In the future, never drive with waste in your black tank. If you have to, dump and flush as soon as your arrive at your destination.

Very doubtful that it is water deposits from hard water as it is designed to drain when the water pressure is removed. Of course, it won't drain if it is plugged up with poop.

Rendon · 05-22-2018, 09:07 AM

My problem is I don’t see where the back flush water line comes into the black tank! Anyone know where it’s located?
I looked at the diagrams on winnebagoind.com but that was not helpful at all.
Thanks
Peggy

luvlabs · 05-22-2018, 09:54 AM

I'm not familiar with your coach so I don't know how the tanks are laid out. You are going to have to open all access points to the tanks and follow the line. You might want to call Winnebago and see if they can help you locate where it is attached to the tank.