Answered Shower not draining properly

[Smk52]

We have a 2018 Jayco Greyhawk 29mv which is new to us and we are having a problem with the shower draining. Have done all of the usual things, drains not plugged, replaced air admittance valve, RV is level, grey water tank is not full. Water is very very slow to drain unless grey water dump valve is open. Called Jayco to ask where the grey water tank vent is and was told there isn't one. Any help will be greatly appreciated.

 

[Buly]

The tank should have air vent. The displaced air from the gray water entering the tank should be vented. Opening the dump valve relieves the air pressure and the shower drains properly.

 

[Smk52]

Then do you know if the Jayco 2018 has a grey water tank vent. Thank you for taking the time to respond.

 

[Buly]

I’m not familiar at all with your RV, but all tanks should have air vents. On my coach they are led all the way to the roof. They are plumbed to the high end (top) of the tank, and usually a hose is plumbed somewhere higher on the rv.
Vents work while filling or emptying the tank

 

[Smk52]

Thanks

 

[TheLooks]

Check the vent that is on the roof, it may be plugged and the problem is only apparent in the tub, for now.

 

[Smk52]

Thanks I will check that.

 

[Buly]

Mud dobers like to build their nests in hoses, pipes etc.

 

[RandyB]

Not sure of how your RV is built, but I think it's common to have a check valve in the drain line. It prevents backing up grey water from a full tank into the shower. Also known as a backflow preventer. If equipped, there is usually a warning sticker somewhere near the drain warning that tools and drain cleaners may damage the valve. Typically, the valve gets cluttered with hair, especially if there is a long hair user. The clog can be retrieved, but care must be taken to prevent damage. You just can't just jam stuff down the drain. Small, flexible mechanical finger grabbers are what can be used.

Think of the drain check valve as a thin, very flexible rubber duckbill inside the pipe. It allows flow easily in one direction, but when flow wants to reverse, the duckbill closes. Remove the grate from the shower floor. Start with only short penetrations to try and capture the clog. on mine, the check valve was about 10 to 12" downstream from the grate.

Warning, once you get the big wad and start extracting it, it's nasty. You'll need a strong stomach.

 

[AbdRahim]

I also occasionally pour some Dawn down all the drains to try to dissolve any grease which can hold hair etc. Dawn is even great for unclogging the toilet in the S&B.

 

[Smk52]

To follow up, I determined (despite what the Jayco tech told me) that the grey water does in fact have a vent that ties into the black water vent that goes to the roof. Applied low pressure air (30 PSI) to the water connection that is used to flush the black tank. Air bubbled up through the shower drain. Went to the roof and connected a plastic bag around the roof vent and had zero inflation of the bag. To me it was obvious that the vent was totally plugged. I expected to see one of those mud nest when I removed the cap but instead I discovered the quality people at Jayco had the pipe sticking up so high that the cap completely sealed it off. Removed about 3/8 inches of pipe and problem solved. Which tells me there has never been an active vent from day one. It might have worked if the cut on the pipe had been a little crooked but the cap made a perfect seal.

 

[AbdRahim]

Glad you found the answer. It seems to take two to three years to get all of the bugs worked out on these things. It can be frustrating at times.

 

[Buly]

Glad you solved the problem.
But you are lucky did not blow up a tank or a connector somewhere by applying 30 psi air pressure to the system. 30 psi maybe ok for your car tires, but for the plastic tanks could be disastrous.

 

[tmac11]

I have the same issue on my 2023 coachman leprechaun. The sinks tend to push water in and up the shower drain.
Snaked the shower, Blue air in the shower - it vented up and leaked out the vent pipe that went to and out the ceiling roof. The vent pipe connects to the sink pipes which somehow ties in to the shower drain pipe I think through an S trap as far as I can tell. I snaked the vent pipe from the roof past the sink connection - no blockage!

All drains great and fast if the gray tank valve is open. I fixed this by removing the one-way ball in the backwash connection at the top of the gray tank. For now that has released the pressure buildup in the tank and all are draining now with the gray tank valve closed.

Not sure if the vent pipe is connected to the gray tank as I can not access the piping at all but has to be somehow as the sinks drain. The main piping is under the shower pan that is recessed in the raised floor and right above the gray tank. I know it is connected to the sinks as can see that by removing a back panel drawer under the sink.

Good enough for now as I have spent hours upon hours trying to fix this!


Good luck everyone! Will just have to keep an eye on the gray tank!

BR tim

 

[sanda]

Not sure of how your RV is built, but I think it's common to have a check valve in the drain line. It prevents backing up grey water from a full tank into the shower. Also known as a backflow preventer. If equipped, there is usually a warning sticker somewhere near the drain warning that tools and drain cleaners may damage the valve. Typically, the valve gets cluttered with hair, especially if there is a long hair user. The clog can be retrieved, but care must be taken to prevent damage. You just can't just jam stuff down the drain. Small, flexible mechanical finger grabbers are what can be used.

Think of the drain check valve as a thin, very flexible rubber duckbill inside the pipe. It allows flow easily in one direction, but when flow wants to reverse, the duckbill closes. Remove the grate from the shower floor. Start with only short penetrations to try and capture the clog. on mine, the check valve was about 10 to 12" downstream from the grate.

Warning, once you get the big wad and start extracting it, it's nasty. You'll need a strong stomach.

This is used in drains when conventional p traps are not used. Don't ever use a plunger on that drain or you will collapse it.

 

[tmac11]

This is used in drains when conventional p traps are not used. Don't ever use a plunger on that drain or you will collapse it.

Thanks - the plumbing schematics show a S-trap under the shower. I know the sinks have the flex backflow drains. Any case, once i removed the check valve on the gray tank for the backwash line, everything drains fine now with the main valve closed as it now vents the air out that backwash line at the very top of the tank! Problem solved! :0