Shower Drain

[CWRoady]

Hoping for help resolving a slow/non-draining shower on my 2008 Melbourne 26A. This is our only continuing problem since our purchase of this MH a little over a year ago.

If the grey tank valve is open, the shower drains perfectly. If dry camping and the grey tank valve is closed, the shower drain backs up quickly, and requires repeated plunging to drain.

Maybe pertinent info:
1) All sink drains work perfectly.
2) I have snaked the drain and it is clear.
3) I have snaked and run water (via a garden hose) down the vent from the roof and it is clear.
4) My grey tank sits below the shower drain.

I have been assuming it is a venting problem based on the info above, yet the problem continues even after I have satisfied myself that the vent and drain are clear .. any suggestions on what to check would be welcome.

[Marcm157]

I would have bet my bottom dollar it was a vent issue. Every fact laid out above indicates as such. I am assuming you checked any Air Admittance Valves on any fixtures that may feed that particular tank? Do any other drains runs even remotely slow?

[TWP723]

I agree, sounds like a venting issue. Just like in your house, every drain needs venting. Kinda like putting a hole on each side of a juice can.

[Scoutmaster253]

It is possible that this would happen if the VENT line was actually in the wrong place. If the vent it extends too far into the tank (like all the way to the bottom) it would pass these tests if the drain is open, but it would not work (vent) if the level of the liquid in the grey tank rose above the opening for the vent.
Is this vent line a flexible hose, or is it a larger diameter rigid pipe? If it is flexible, is it attached to the wrong port on the grey tank?

[Berjr]

Originally Posted by Scoutmaster253

It is possible that this would happen if the VENT line was actually in the wrong place. If the vent it extends too far into the tank (like all the way to the bottom) it would pass these tests if the drain is open, but it would not work (vent) if the level of the liquid in the grey tank rose above the opening for the vent.
Is this vent line a flexible hose, or is it a larger diameter rigid pipe? If it is flexible, is it attached to the wrong port on the grey tank?

This is just what is was thinking Vent pipe maybe too low in the tank

[CWRoady]

Thank you for the help thinking about this problem and possible solutions.

I have checked the kitchen air admittance valve and the top vent cap. I hadn’t really considered a construction defect (the vent being too deep in the grey tank) due to the age of the MH (2008). That thought certainly syncs with the symptoms though. Hard for me to imagine this problem existing since day 1 and previous owners just accepting it, but who knows?

Any thoughts on how to confirm the as-built vent to grey tank connection?

[mini4mw]

based on the specs, you have 1 gray tank:
https://www.rvguide.com/specs/jayco/...ourne/26a.html

If it is the pressure relief on the tank, it should happen from sinks as well. I don't think I saw that you tested that. I'd grab some water pitchers, buckets, etc and fill up the kitchen and bathroom sink and see if it has the same issue. You might see backup through the shower drain. If this happens then certainly sounds like the gray tank breather, and thats much better than the black...

I have one of those cheap snake cameras. Maybe a friend has one for you. One of those things you rarely use but sure comes in handy. This is the one I have and I'm happy with it. Has a good light too.
https://www.amazon.com/gp/product/B08NJ8627V

If you have one of those you can stick up the grey outlet and start looking around the best you can and see what you can find.

I wouldn't use a plunger to clean it out anymore though as if the lines are clear you are building up pressure and asking to blow a seal somewhere possibly making a bigger mess.

If it is the issue, I think you'd have to cut a hole in the tank, cut the tube and then seal it back up with fiberglass or some patch material.

[Marcm157]

Originally Posted by CWRoady

Thank you for the help thinking about this problem and possible solutions.

I have checked the kitchen air admittance valve and the top vent cap. I hadn’t really considered a construction defect (the vent being too deep in the grey tank) due to the age of the MH (2008). That thought certainly syncs with the symptoms though. Hard for me to imagine this problem existing since day 1 and previous owners just accepting it, but who knows?

Any thoughts on how to confirm the as-built vent to grey tank connection?

How far of a run is it from the dump valve to this gray tank? I have used a borescope on many occasions to have a look at things out of reach. You can get relatively inexpensive "camera snakes" Go up from the dump valve into the tank and you should be able to see the vent pipe.

[CWRoady]

A friend does have one of the iPhone compatible endoscopes. I'm on it once I can get over to his place to borrow it, thanks again. I will close the loop with what I find.

[Scoutmaster253]

Looking forward to hearing what you find.