Rv sink to outdoor sink

[Atin17]

This might be weird but maybe y’all can help... I noticed my kitchen sink would clog & water had a hard time going down, I tried plumbing it work very little , snaked it, hardly nothing came out.. I unscrewed the (cheater trap) in the sink & it went down without coming up .. I thought great news.. until I noticed water coming out of my outdoor kitchen sink while I had the indoor kitchen sink running.. sounds confusing but maybe y’all can help I’m thinking there’s a check valve fault but my knowledge to check valves in rvs is little to none. I have a crossroads high country 32rl ..

[Lloyd]

Sounds like the holding tank is full. Are both sinks plumbed into the same holding tank?
On some of there units they let the outside sink run on the ground. Some had their own holding tank, and some were plumbed into the main grey tank.
What year is your rig?

[travelin texans]

Originally Posted by Atin17

This might be weird but maybe y’all can help... I noticed my kitchen sink would clog & water had a hard time going down, I tried plumbing it work very little , snaked it, hardly nothing came out.. I unscrewed the (cheater trap) in the sink & it went down without coming up .. I thought great news.. until I noticed water coming out of my outdoor kitchen sink while I had the indoor kitchen sink running.. sounds confusing but maybe y’all can help I’m thinking there’s a check valve fault but my knowledge to check valves in rvs is little to none. I have a crossroads high country 32rl ..

If you used a plunger & a snake on the Hepvo (cheater) trap you likely messed up the rubber bladder with the snake or sucked inside out with the plunger. That thing has what looks like a piece of bicycle inner tubes that's flattened out, so a replacement is probably on your to do list.
I also agree it appears you have a full grey tank, don't count on the tank level sensors to give you any useful accurate information.

[dagst1]

I agree that it sounds like your tank is full. The kitchen sink is higher than the outside kitchen one so if the tank is full it would drain thru the lowest exit.

If your tank is indeed empty you could have pushed something past the junction of the two sinks and the line into the tank is still blocked.

Have you checked the tank level?

[Atin17]

Thanks for the replies guys yes it’s connected to both holding tanks.. but the Gray valves are open all the time I never close the valves other then the black tank.. & about the rubber part I disconnected the contents including the Hepvo trap before snaking the outdoor drain.. it’s a 2015 I noticed I put high country it’s a hill country . Again it’s just kinda weird how when I run water through my kitchen sink it drains out I would say 40% through where it’s supposed to the other 60 out the sink I came up with these numbers cause I emptied out the drain hose to sewer & ran water & noticed it was still draining but not all of it. The other 60% was going out to the kitchen . Maybe there’s a check valve somewhere down where the 2 pipes cross before entering the Gray tanks . Thanks again guys for helping hopefully we get this resolved

[dagst1]

When we bought our Cruiser it had spent several years on a lake lot. The owners kept the gray valves - 1 kitchen and 1 bath/shower - open. After using it for a short period of time the kitchen drained very slowly. A little flow then just a trickle for a very long time. Jump ahead to a expensive plumbers bill involving a camera which reveled a lot of grease built up in the tank outlet. Took a long time to get it cleared out but now it drains well.

The cause : the drain valve left open and the liquids would drain off and left the kitchen solids/grease behind. So after this lesson we leave ALL valves closed then fill the tanks before we dump to help the flow and clean the tanks better.

Can you see the drain from the outside sink and follow it to the other line? you may have to drop the under belly. There maybe a check valve in that line.

[Atin17]

Originally Posted by dagst1

When we bought our Cruiser it had spent several years on a lake lot. The owners kept the gray valves - 1 kitchen and 1 bath/shower - open. After using it for a short period of time the kitchen drained very slowly. A little flow then just a trickle for a very long time. Jump ahead to a expensive plumbers bill involving a camera which reveled a lot of grease built up in the tank outlet. Took a long time to get it cleared out but now it drains well.

The cause : the drain valve left open and the liquids would drain off and left the kitchen solids/grease behind. So after this lesson we leave ALL valves closed then fill the tanks before we dump to help the flow and clean the tanks better.

Can you see the drain from the outside sink and follow it to the other line? you may have to drop the under belly. There maybe a check valve in that line.

Having to get under the belly is the last thing I’m hoping for I’m a first time rv”er & this is the only serious problem I’ve had .. I replaced the cheater valve & it’s been working fine the kitchen. I guess the problem is from the outdoor sink to the holding tank to the main drain . Anything in there I can try snaking again I just don’t wanna mess anything up.

[travelin texans]

I wouldn't recommend using a snake on any rv plumbing, it's all plastic so you could possibly snake a hold through the tank, not mention once it enters the XX? gallon tank it'll just flop around everywhere.