bathroom sink BURPS

[Ford truck guy]

So, I have a 2020 3991RD, the bathroom sink and shower both drain into the same grey tank. When the tank valve is closed, I take a shower and the sink will burp up water... It like a vent is blocked?? And YES, the tank is EMPTY.. There is a screw on vent under the sink, would that be the one that needs to be replaced?

[XCMARK]

any chance the tank vent has dropped into the tank and not threw the roof? you may want to pull the tank vent cover on the roof and see if the pipe is to long and attached at the top. Tape measure with a hook should work and a flash light. Maybe a bee's nest in the vent ?

[Ford truck guy]

Originally Posted by XCMARK

any chance the tank vent has dropped into the tank and not threw the roof? you may want to pull the tank vent cover on the roof and see if the pipe is to long and attached at the top. Tape measure with a hook should work and a flash light. Maybe a bee's nest in the vent ?

Thanks Mark , That is this weekends chore for me. I replaced the old, cheap air admittance valve today with a Studor Valve I purchased at Lowes... I had to use a Rubber Fernco fitting as the pipe under my sink is male end and all the valves I found were also male end. This was the easiest solution I could come up with.

[GTXRAS]

I'll take a shot, Could the silicon flap in the Hepvo valve for the sink be turned around? Tank vents back to the sink during a shower. The water in the sink could be coming from the U under the sink.

We have an MB and in some very strong winds one time, the Hepvo flap got turned for our 1/2 bath.

Rick

[Ford truck guy]

Originally Posted by GTXRAS

I'll take a shot, Could the silicon flap in the Hepvo valve for the sink be turned around? Tank vents back to the sink during a shower. The water in the sink could be coming from the U under the sink.

We have an MB and in some very strong winds one time, the Hepvo flap got turned for our 1/2 bath.

Rick

Is the hepvo valve the same as the little round air vent under the sink?

[GTXRAS]

https://hepvo.com/hepvo-waterless-valve/

No

[Ford truck guy]

Originally Posted by Ford truck guy

Is the hepvo valve the same as the little round air vent under the sink?

My vent is not that.. I have a pipe sticking up with a vent cap on top of it under the sink

[GTXRAS]

That should be in the drain pipe for the sink, possibly. Maybe it depends on the model.

[XCMARK]

Joe , Did that fix the issue with the burp?

[Ford truck guy]

Hey Mark,

I am not sure yet. My time has been consumed by other things.. I am also not camping so I can NOT test anything out. I still have to go onto the roof and peek down the vent to see if there are any blockages there?

I will get everyone an update once I have looked at everything, and once I had a chance to verify all is either fixed, or not.

[Ford truck guy]

So,

I changed the vent under the sink and upgraded to the Stupor valve... I am ASSUMING that original valve was bad as when I removed it, it sounded like loose pieces inside somewhere..

I went onto the roof, pulled both caps off and took my fiberglass plow markers that are 1/4" diameter and 48" long.. I fastened 3 together and marked the depth that I THOUGHT it should go..

I lowered it into each pipe from the roof and each went all the way down to the bottom where I heard a plastic sound as I raised a few inches and dropped...

BOTH pipes were sticking out from the roof approximately the same length as the other..

SO.... I am thinking it was the vent under the sink... It will be a while before I will be out camping again to try it out.

Joe