MBS 2016 Black Tank Scrubber

[stervin]

Hello
The other day after dumping black and then grey tank we hooked up the hose to the black tank scrubber.
Have done this for the past 3 years and it does a great job of getting the side walls cleaned.
This time Low and Behold we were greeted with water blowing out of the air vent under the bathroom sink and no sound from the internal scrubbers.
Yes discharge valve was open but nothing came out only clear water from the air vent.
Curious if any of my fellow Glampers can give me some pointers of why and possible corrections
Thank Y'all in advance and safe travels

Steve

[Bama Rambler]

That air vent is the backflow/anti-siphon device for the tank rinse. They fail pretty often.

Does it look something like this?

[stervin]

Originally Posted by Bama Rambler

That air vent is the backflow/anti-siphon device for the tank rinse. They fail pretty often.

Does it look something like this?

Yes looks the same but black
Would that cause the problem ??
Thanks for your feedback

[stervin]

Any ideas where I can purchase a new one

[Bama Rambler]

That one is from Amazon It's a Valterra A10 3050
Most RV places will have them too.

[MNtraveler]

How/why is the bathroom sink connected to the black tank not the gray tank?

[AudiDudi]

Originally Posted by MNtraveler

How/why is the bathroom sink connected to the black tank not the gray tank?

I'd guess a shorter line to the tank and likely easier to install.

[MNtraveler]

Perhaps but usually the bathroom sink is quite close to the shower...

It’s not a bad thing and could be a good thing for adding more water to the BW tank. It’s just something an owner would kind of like to know.

[AudiDudi]

Originally Posted by MNtraveler

Perhaps but usually the bathroom sink is quite close to the shower...

It’s not a bad thing and could be a good thing for adding more water to the BW tank. It’s just something an owner would kind of like to know.

I would think that the amount of water from the sink would not be much as compared to the shower - kind of a nit as to overall volume of water going into the black tank.

[MNtraveler]

Originally Posted by AudiDudi

I would think that the amount of water from the sink would not be much as compared to the shower - kind of a nit as to overall volume of water going into the black tank.

If the bathroom sink and shower are both drained to the black tank, then there would be very little need for the gray water tank (kitchen sink...). I would think in the vast majority of cases, the shower is routed to the gray water tank.

[namusmc]

Wondering if my 2401W bath is configured the same way.

[bubbles]

The black tank cleanout is a self contained system that is routed directly from the outside input port to the black tank through the backflow preventer/check valve (which has nothing to do with any other plumbing, sink drain etc.). The backflow preventer/check valve has to be installed at least 6 inches above toilet rim and routing it under the vanity was a convenient place to hide it. The routing could be anywhere in other rv's.

[barnbnb]

Originally Posted by namusmc

Wondering if my 2401W bath is configured the same way.

On the W model the inlet for the black tank scrubber comes through the outer wall into the area under the sink. The sink is not connected to the scrubber in any way. The sink cabinet simply serves as a chase for the scrubbers' plumbing.

I found that the line between the inlet and the scrubber valve was broken on mine, probably caused by freezing from improper winterization at the dealer. I fixed it myself with plumbing parts I had on hand.

It is easy to overlook that line in the winterization process. Put it on your checklist.

[AudiDudi]

Originally Posted by MNtraveler

If the bathroom sink and shower are both drained to the black tank, then there would be very little need for the gray water tank (kitchen sink...). I would think in the vast majority of cases, the shower is routed to the gray water tank.

I see I worded that poorly. The shower and kitchen sink go to the grey tank - the toilet and bathroom sink to the black tank. Brushing one's teeth does not add much water to the black tank

[namusmc]

Originally Posted by AudiDudi

I see I worded that poorly. The shower and kitchen sink go to the grey tank - the toilet and bathroom sink to the black tank. Brushing one's teeth does not add much water to the black tank

What?! You have teeth?

[Rkloud9]

Originally Posted by barnbnb

On the W model the inlet for the black tank scrubber comes through the outer wall into the area under the sink. The sink is not connected to the scrubber in any way. The sink cabinet simply serves as a chase for the scrubbers' plumbing.



I found that the line between the inlet and the scrubber valve was broken on mine, probably caused by freezing from improper winterization at the dealer. I fixed it myself with plumbing parts I had on hand.



It is easy to overlook that line in the winterization process. Put it on your checklist.

Like yours, my SunSeeker MBS 2400W has the black tank flush routed through the passenger side under the bathroom sink to a check valve, and on down to the black tank. My understanding is that the check valve protects the fresh water line from the rather unlikely possibility of a waste water backflow. No water is present in that line except when flushing, so it does not seem likely that there is any possibility of freeze damage. What am I missing?

Thanks!

[MNtraveler]

Originally Posted by Rkloud9

Like yours, my SunSeeker MBS 2400W has the black tank flush routed through the passenger side under the bathroom sink to a check valve, and on down to the black tank. My understanding is that the check valve protects the fresh water line from the rather unlikely possibility of a waste water backflow. No water is present in that line except when flushing, so it does not seem likely that there is any possibility of freeze damage. What am I missing?

Thanks!

There could be a bit of water left in the device, but it seems unlikely or that it would cause damage - but by this report (earlier in thread) it did.

A relatively easy way to winterize the BW flusher while pumping in antifreeze is to hook up the external sprayer hose to the BW flusher then attach it to the external sprayer outlet and turn on the water pump for a few seconds. (That will also take are of the external sprayer line!)

I think I did this once but maybe not last year, so I'll have to remember it again this fall.

If not using antifreeze (which we definitely do in these parts), one could just hook up the air pressure line hose end adapter to the BW flush port and blow it our for a few seconds.

[barnbnb]

Originally Posted by Rkloud9

Like yours, my SunSeeker MBS 2400W has the black tank flush routed through the passenger side under the bathroom sink to a check valve, and on down to the black tank. My understanding is that the check valve protects the fresh water line from the rather unlikely possibility of a waste water backflow. No water is present in that line except when flushing, so it does not seem likely that there is any possibility of freeze damage. What am I missing?

Thanks!

Although proper installation of the check valve plumbing requires attaching it to the inside of the sink cabinet, that step was skipped when mine was built. Go figure. It should be secured in a manner so that any water left in that very short section of plumbing leading to the check valve drains back out via the inlet.
As mine was not secured properly, it drooped down which allowed water to remain in the line. I assume that the line broke from freezing, but it is also possible that the line fatigued from bouncing around during travel.
The factory just staples the line in place through plastic ears. Except for mine, ha! After I repaired the defective plumbing, I used metal strapping and screws to hold it in place.
It's a good idea to check it out to make sure it is fastened down correctly.