sink holding tank

[exit55]

Have 2016 Thor Vegas MH. Bathroom sink would not drain. Shower worked fine. Used plummer helper on sink and it went down some. Sink could get to drain. Grey water tank not full. Noticed that water level in commode was elevated. Open black water tank dump. Tank was full. Water went down in sink. Appears that sink drains into black water (shower to grey water). Is it suppose to be this way. Always thought sink went to grey water.

[Beau388]

Originally Posted by exit55

Have 2016 Thor Vegas MH. Bathroom sink would not drain. Shower worked fine. Used plummer helper on sink and it went down some. Sink could get to drain. Grey water tank not full. Noticed that water level in commode was elevated. Open black water tank dump. Tank was full. Water went down in sink. Appears that sink drains into black water (shower to grey water). Is it suppose to be this way. Always thought sink went to grey water.

Thor MC plumbs nearly all the bathroom sinks into the black water tank. The reason is to add extra water to the black tank to help flush out the solids when dumping. Most RV toilets do not add enough water in the flush sequence. This is especially important if the toilet is on the right side of the coach. Where everything drains and how to dump should have been covered in the PDI by the delivery tech, as there are significant differences among the different manufacturers.

[TurnerFam]

it's not necessarily plumbed that way 'just for helping the black tank', but mostly to do with the sink being already close to the toilet and black tank, many times on the same side of the coach, and easier to plumb. Many RVs certainly have their drains to the gray tank and toilet to the black tank, just like mine.

but, regardless, does it really matter? no. either tank is simply a tank for holding waste, whether 'black' or 'gray'. Most will argue that they would RATHER the sink drain into the black tank as it tends to help with the GRAY tank filling faster than the black, which is what most of us encounter.

but, no, there's no 'rule' or 'law' that only the toilet is plumbed to the black tank, but simply that the black tank is labeled that BECAUSE the toilet is plumbed to it.

[Bob Denman]

Now that this has been "cleared up": welcome to the forum!

[Judge]

I tend to agree with Beau....

The shower is also typically located closer to the black tank but it always goes to the grey tank while the bathroom sink usually goes to the black tank.

If you flush the toilet properly (filling the bowl just about to maximum to ensure that waste is pushed to the bottom of the tank and to help keep debris off the sensors), you should get enough water for proper dumping. The bathroom sink is usually small and typically uses less water than kitchen sink and can help the black tank have enough water to dump properly and it also helps to balance the input to the holding tanks.

The kitchen sink typically uses much more water along with the shower so they will go to the grey tank.

[Travelin' Texans]

My wife has a BIL, I ain't related to him thank goodness, that owned a RV for 15 minutes & knew everything there was to know about them, at least thought he did, much like the so called "engineer" mentioned. You only had to talk to him about 2 minutes to find he didn't know sh#$ about RVs or much else.
It's not unusual though to have a bath sink drain into the black, some depending on tank locations others just 'cus.

[Bob Denman]

You can always tell a Brother-in-Law...


... But you can't tell him much!

[exit55]

Thanks everyone for reply. Saved me a lot of time.

[EA37TS]

It depends on the coach and how the plumbing can be routed. On our Challenger 37ND the only thing that went into the black tank was the toilet. The shower and outside sink went into one grey tank and the kitchen and bathroom sinks went into the other grey tank. The grey water was actually based on the side of the coach. Driver's side into one grey tank and passenger's side into the other.

On our Accolade the toilet goes into the black tank and everything else into the grey tank.

[Beau388]

There are always exceptions. Our first class A had a macerator in the toilet and one in the kitchen sink drain were macerators pumped into the black tank. The shower and bath sink went into the gray water and the gray water was used to flush the toilet via a flush pump..

[lwmcguire]

Our Tuscany is plumbed with the 1/2 bath going into the black along with the 1/2 bath toilet

Kitchen sink, shower, washer, full bath macerator toilet and sink drain to the grey
The grey is a 1.5 inch drain line vs the 3 for the black

[EA37TS]

My suggestion to the OP is to go to the owner's resource center and pull down the plumbing diagrams and if they're not available to contact Thor and ask for them.

[lwmcguire]

Originally Posted by EA37TS

My suggestion to the OP is to go to the owner's resource center and pull down the plumbing diagrams and if they're not available to contact Thor and ask for them.

Great place to start and need the info filed anway.

then verify it if needed by adding water and monitoring levels