shower and kitchen sink won't drain

skier1950

Member
2015 SS Agile; shower and kitchen sink takes forever to drain. Saw this problem posted a long time ago but there was no solutions to the problem listed. Has anyone had this problem and solved it?
 

starfighter

New member
I did have a problem with shower not draining. Found that if I had the front of vehicle slighted elevated, problem solved.
( I would also check the vent for grey water tank)
 

irvingj

2015 RT SS Agile (3.0L)
How "full" is your gray water tank? Just to check it out, we allowed ours to pretty much fill up; sink drain became extremely slow at draining- thought it was stopped up, but no, tank was full. It did eventually drain, or seemed to. Draining holding tank(s) fixed it.
 

johnboater

New member
I had this problem with my new '16 Agile I got last month. Took first shower morning after I got it and was soon standing in water. I worked it over with plunger over several day period. Even wrapped business end of hose with small towel and forced water in. Working fine now.
 
There was a mention on the Roadtrek Owners Group on Facebook that Roadtrek has a fix for the Agile slow drain problem. You might want to join the group to connect with other owners.
 

starfighter

New member
After talking w/ Roadtrek, this is a known condition.
They gave me the part number for a repair kit and will cover installation under warranty
 

RT.SS

Active member
The Roadtrek fix is probably to change the “air admittance valve/ anti-siphon valve” under the sink due to slow kitchen drain, but that has nothing to do with the slow shower drain problem. It is just a bad shower drain design in my opinion. The shower drains into the gray tank via the same pipe for the gray tank vent; in right conditions, this design is prone to vapor lock in the tank. It’s like funneling water all at once into an air tight container, what are they thinking? If you look at the attached picture below, the shower drain/vent pipe is also almost vertically mounted compounding into the slow drain problem. :2cents:
 
Did they recently change the plumbing? The Agile has been around on this chassis since 2008 and the reports of drain problems seem to be recent...
 

RT.SS

Active member
My 2011 Agile (built in 2010) suffers same problem when it was new, sometimes it won’t drain at all. If I open the anti-siphon valve it drains quicker so it appears to be vapor lock in the tank, at least in my experience. The shower drain has gotten slightly better…why? I don’t know as I didn’t do anything to correct it. I barely used the shower anyways. I can only speculate that the plumbing now has slimy coating from soapy sediments and the water drains slightly better with less resistance???
 

starfighter

New member
Did they indicate what was being fixed with the repair kit?
They did say that the "fix" was to elevate the drain.
I believe they meant elevate the VENT.........
because when experiencing the problem I discovered that although the grey tank was almost empty, an amount of water came out the vent while I was trying to force the water down the shower drain.
This led to my idea that the angle of the Agile was causing water to block the vent, so I repositioned the Agile so the front was slightly ( and I do mean slightly) higher than the back.
The standing water in the shower drained immediately, which indicated to me that where the water had leaked near the front of the tank was where a vent was located and the theory of blocked vent may have been correct. On our forthcoming trip, I am taking a length of flex. tubing and if the drain plugs, will insert the tubing into the drain to introduce air into the system.
A dealer has ordered the repair kit for me and will install it on our return.
 

RT.SS

Active member
They did say that the "fix" was to elevate the drain.
I believe they meant elevate the VENT.........
because when experiencing the problem I discovered that although the grey tank was almost empty, an amount of water came out the vent while I was trying to force the water down the shower drain.
This led to my idea that the angle of the Agile was causing water to block the vent, so I repositioned the Agile so the front was slightly ( and I do mean slightly) higher than the back.
The standing water in the shower drained immediately, which indicated to me that where the water had leaked near the front of the tank was where a vent was located and the theory of blocked vent may have been correct. On our forthcoming trip, I am taking a length of flex. tubing and if the drain plugs, will insert the tubing into the drain to introduce air into the system.
A dealer has ordered the repair kit for me and will install it on our return.
I don’t think the water leak is from the gray tank vent, there is probably a leak in the gray tank plumbing. Have them check that out when you drop the RV for repair. I could not imagine RT adding a gray tank vent under your rig, if they do, that would be bad as gray tank fumes could creep up inside the van, not to mention gray tank contents leakage into the ground when tank gets full. Holding tank vents are usually vented into the roof.

Elevating the shower drain plumbing makes sense so it slopes downward into the gray tank for better gravity draining. I’m also curious about that repair kit.
 

skier1950

Member
I just spoke to Peter Lange @ RT. The repair kit is called a grey tank vent kit. It's only been available for a few weeks.
Part # 99920050. Peter says it should take care of the problem. I'm crossing my fingers!
 

just4grins

New member
We just purchased a 2014 MB Sprinter RoadTrek Agile and saw the air lock issue being discussed. We just sold our 2014 Casita 17 SD which had the same problem for a while. Someone came up with a permanent fix by installing a "vacuum break" line from the top or high side of the gray tank and fed it to the drain vent pipe above the height of the gray water. Bingo, problem solved and never came back. This sounds very similar.
 

skier1950

Member
I had the vent kit installed and now things seem to be draining ok. We'll see if it continues to be over the long haul.
 

skier1950

Member
I'm not sure. I wasn't allowed in the back to observe the repair and didn't bother asking. I was only interested in the results, not the procedure. Call RT.
 
Don't have any problems with the drains on mine, Just was going to pass the info along to others on the Roadtrek Owners Group who do have the issue...
 

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