Black tank backed into shower and sink?

[charliez]

the backfill pressure going the other direction they can get mixed


This is a complete line of BS. If that were the case, how would you know that the valves can be installed backwards and let it leak out. The valves are blades that close, like a door. Sounds to me like you need to get it back and get under it and look at the pies yourself. Put hands on them and see how they are connected. I hope your not paying for that answer.




This is what the valve looks like. Smaller for grey tank, different logo or no logo depending on mfg.


https://www.amazon.com/Valterra-T100...=fsclp_pl_dp_2

[dped]

Originally Posted by charliez

the backfill pressure going the other direction they can get mixed


This is a complete line of BS. If that were the case, how would you know that the valves can be installed backwards and let it leak out. The valves are blades that close, like a door. Sounds to me like you need to get it back and get under it and look at the pies yourself. Put hands on them and see how they are connected. I hope your not paying for that answer.




This is what the valve looks like. Smaller for grey tank, different logo or no logo depending on mfg.


https://www.amazon.com/Valterra-T100...=fsclp_pl_dp_2

I don't believe the mix is occuring at the valves near the dump gate, I believe it is happening further up the system. Luckily no, I didn't pay for that answer but I do think it is correct as far as ventilation goes but could be something else.
Unfortunately (or fortunately maybe) I can't actually see how any of the pipes are routed from underneath. I can see the tanks and how they dump, but not how anything is routed into it without tearing the inside apart.

[Old-Biscuit]

Why not contact THOR and request plumbing diagrams....especially the waste tank/piping/vent diagrams?


Customer Care Form
https://www.thormotorcoach.com/customer-care/


Customer Service (877) 855-2867

[hohenwald48]

Originally Posted by charliez

the backfill pressure going the other direction they can get mixed

This is a complete line of BS. If that were the case, how would you know that the valves can be installed backwards and let it leak out. The valves are blades that close, like a door. Sounds to me like you need to get it back and get under it and look at the pies yourself. Put hands on them and see how they are connected. I hope your not paying for that answer.

Not necessarily "a complete line of BS." It's possible that the black and gray tanks share a vent line and are tied together just above the tank level. Under normal usage the two would remain separate. However, if backfilled and allowed to over flow up into the vent stack then water would move from the black side over into the gray side filling that tank too. It would then eventually flow into the shower.

[powerboatr]

i have seen some with high pipes in the gray tank that will flow to the black tank if the grey gets full,

maybe yours is set up like that.

this gives you a bit of a cushion if grey tank gets over filled before you can drain it.
my damon has the grey and black tank sharing one vent pipe through the roof, they split in the wall about 2 feet above the tanks. so if water gets that high...we have a shower flooding the coach.


if you are rinsing the black or grey tanks. you should never fill them all the way.

we fill to about 1/2 and then drain out. I also have tornado flushers on both tanks

[CWP3]

I talked to Thor today. They told me that

• the main bathroom’s sink and toilet drain into the main black
• The back bathroom’s (if you have one) toilet and sink drain into the back black tank
• All other sinks (to include outside) drain into the grey

They drain those sinks into the black tanks to ensure sufficient liquid in the black tanks.

[Jay D.]

did they tell you where the shower drains. you say water came up through the shower and bath sink. unless there was to much volume with the back flush you should never be able to have water come out of the sink. it would just fill the shower as the sink is above the shower drain.
Jay D.

[CWP3]

They told me that the shower drains into the grey tank.

[EdInArk]

Originally Posted by dped

I've got a 2017 Thor Four Winds 30D
I'm used to having a black tank quick connect hose connection to clean out the tank but this one doesn't have it so I bought a Rhino Blaster Pro and used that to backfill the black tank as per it's advertised use.
I emptied the black tank then turned on the hose to begin the backfill and rinse but underestimated how quickly it would fill up. Water came up into the toilet bowl as expected but at the same time the bathroom sink and shower also filled up with some nasty water while I was sprinting back outside to turn off the hose.
After draining the black, I drained the gray but also found that the gray had been very slightly cracked open, so to test again I closed it tight and back filled the black all the way up again keeping a closer eye on it. Again, water came out of the tub and sink.
How could filling up the black tank cause this?

Edit: not sure if related but the kitchen sink drains very slowly and gets hardly any water pressure. May not be helpful, but maybe that's a clue to something...

Our bathroom sink drains into the black tank. I discovered this the same way you did

You said the first time the "gray had been very slightly cracked open", so my guess is that it was enough to fill the gray as well the first time, and it came up through to shower.

After closing the gray, the second time it only came up to the sink. That sink drains into the black, so that's as it should be.

The water pressure and drain at the kitchen would be a separate issue.

Just me guessing from the clues provided.

[twogypsies]

This post is 7 months old so I would think the OP found his answer. It would have been nice if he'd return with the outcome.

[EdInArk]

Originally Posted by twogypsies

This post is 7 months old so I would think the OP found his answer. It would have been nice if he'd return with the outcome.

I'll never learn to check dates. Thanks.

[Gary RVRoamer]

Do the colored water test, but I suspect you will find the RV manufacturer took a shortcut and plumbed the shower and sink to the black tank as a convenience for assembly at the factory. It's not at all unusual for a bathroom sink to be plumbed that way, and occasionally a shower as well. It really simplifies the things at the factory if all toilet, shower and sink all drop directly into the black tank, which needs to be under the toilet anyway.


Just another example of shoddy design shortcuts to make the rig cheaper regardless of the ultimate impact on the buyer.

[cavie]

Rino Blaster Pro is a waist of time and money. Do a you-tube search for a comparison video. OR just think about it. After the hose pressure hits the very 1st 45 or 90 you loose ALL pressure you had and you are just slowly filling the tank. It does not go around any corner with ANY pressure behind it. You can accomplish the same thing by flushing the toilet!

YES, yours and many many others do in fact drain the sink into the black tank. If you filled the black tank with your back wash, the shower is the lowest point in the system and it will come out there. If you opened you toilet valve it would come out there.

I can't think of ANY reason you would need enough water in the black tank to fill it up. For 4 years I have been draining my black tank and rinsing with two full bowl flushes of the toilet. My 2002 Fiver had no back flush fill and never saw any reason to have to use one.

[cavie]

Originally Posted by EdInArk

I'll never learn to check dates. Thanks.

I have the same problem but at least it's there for someone else to read.