question about the 400 flooding from kitchen faucet

rhyno

I've seen a few incidents online where folks have closed the kitchen sink lid on the folding faucet's handle in a way that ultimately backed up the gray tank, flooding their Tab when water backed up through the kitchen sink. Wouldn't the low point be the wet bath's shower drain or does that drain have a backflow preventer on it? Just wondering since the only time we overfilled our gray tank in our old Rockwood, the shower pan is what started filling up.

kellyw

@rhyno - maybe the stopper was in the sink and that’s why it overflowed in that situation. Otherwise I’d expect the shower pan to overflow if the gray tank filled. But I’m not willing to test my theory 😂

but basically with the faucet - you have to have it in the “cold” position so it doesn’t happen in the first place. (handle down and pointed to front not up)

atlasb

learning our 400 when we got it, we found that after running all the water to fill the alde tank and a couple showers,  doing dishes, etc.,that the shower pan will definitely fill when the gray tank is full.  it doesn't take much to fill 18 gallon gray tank.  Now we monitor and when needed drain the gray tank into a couple lidded 5 gallon buckets to take to the drain station.  Rarely we get a corp site that allows discharge of gray water on site.

rhyno

@kellyw - that makes more sense to me that the drain plug would be the culprit. Of course now I can't find the original story that got me thinking about this in the first place to see if they mentioned the drain plug or if they really thought the gray tank backed up through the sink and not the shower pan.

ChrisFix

The gray tank will back up into the shower pan when it's full...there is no where else for it to go.
If someone over flowed the kitchen sink, it's because the strainer was in the closed position. 
That said, it is incredibly easy to shut the sink's glass top and accidently turn on the water - I must have done that a dozen times in my first weeks of ownership!
You must put the faucet handle in the full cold position (all the way down) to avoid that particular mishap.

Denny16

The best solution, is to stow the faucet in the down position and water mix valve either in the middle or down position, then the glass top will not turn the water on.
cheers

[Deleted User]

Just thought I would bump this up to the top as a reminder of how easy it is to close the kitchen sink lid and unknowingly turn on the faucet.  This will end in a major flooding disaster if not caught quickly. I noticed its very easy to do in my new 2022 400... even more so than my 2019 400. 

Denny16

Since this was originally posted, I have discovered that some. 2018/2019 TaB400s have a HEPVO valve instead of a trap on the shower drain, and some did not, but later builds of,the TaB400 have a HEVPO vlalve in the galley sink.  A HEPVO valve will not let water from the gray tank backup into the shower or sink where one is used.  The work like a one way check valve, only allowing flow from sink/shower drain to waste tank or sewer drain.  

If a shower has the HEPVO valve, the gray tank will not backup into the shower pan very easily, until pressure on both sides of,the valve are equal, then water might flow in from tank to shower or sink.  Water backing up the plumbing is going to find the path of least resistance.  If the shower has a HEPVO valve and the galley does not (as was the case in our TaB400, then water will try to back out of the sink.  If the sink and shower both have normal traps or only sink has the HEPVO, then the shower being lower path of resistance, will back up first.
 Cheers 

bergger

Thanks for the info on how the HEPVO works.  I did not know that but makes sense now that you mentioned it.  Our 2021 400 has a HEPVO in the kitchen sink and a standard P-Trap in the shower pan.  I wonder if they did that intentionally so if overfilled the gray water will go into the shower drain pan over the kitchen sink. 

[Deleted User]

The benefit though of having it over flow at the sink is you might notice it quicker than the shower.

Denny16

I am not sure either TabbyShack, but seems logical.  When nüCamp put the HEPVO valve on the galley sink in 2019 TaB400s, they went back to a PTrap on the shower.  The down side to this, it required cutting a hole in the floor under the area where the PTrap is.  It is the shower that fills up the gray tank, so a backup is more obvious in the shower and less likely to go unseen or cause any water damage.

Our TaB400 has the HEPVO on hr shower and a standard PTrap in the galley, which I changed out to a HEPVO valve.  So I dump our gray tank every two days, if not daily. 

Cheers