Gray Water Tank Doesn't Drain

[Texasbassman]

Brand new 2021 Jayco Seismic 3815; one and a half bath (2 black and 2 gray tanks). First time draining the tanks. There is one set of black and gray water tank valves in the pass thru area with the fresh water controls. Another set is just forward of the first axle. I don't have any problems with draining either black tanks nor the gray tank for the 1/2 bath. But the gray water tank for the shower, full bath sink and kitchen sink will not drain. I contacted Gander RV where I purchased and was told to call Service and make an appointment. That doesn't help me in the campground. Anything I'm missing or something else to try?

[Grumpy]

Are you going by the gauges or is water backed up someplace? The gauges are not always accurate.

[RogerR]

Other posts in the past have indicated blockage by construction material left in the tanks could happen. Or your valve was broken when or as installed. Is your valve where you can see it or on a remote cable/rod? Some have reported the valves that are hidden are broken or just not connected.

Search above for blocked gray tank or valve.

[ALJO]

Dealers always want your money, they are not a Free advice institute!
Close all drain-valves except the tank you have trouble with. Place a 3" cap with 3/4 connection; install a water-hose and fill the tank part ways.
If it will not fill, the valve might be stuck.

[Jagiven]

Are you at a CG with full hookups?

It is middle of the week, so Jayco should be in the office. Contact service, have your vin number handy and asked for the waste piping diagram. Be nice, they do not always like to had out schematics on a new rig. If they say no, ask if they would authorize a mobile service call. Jayco will only pay if pre authorized.

I suspect you have a valve issue. When you pull on this grey valve handle, does it have the same resistance as the other valves? Even if you had construction debris, grey water will at minimum weep past the debris.

I foresee two holes being cut in the underbelly. Not a big deal. Sketch a 4 side box on the underbelly, at minimum 6" x 6", only cut three sides. The side closest to the pin (front) do NOT cut (keep it as a flap). Pull down the flap, look in possibly with your phone. Determine where your valve is at. If needed make a second hole, were you find the valve. Can you see the connecting rod? Can someone pull/push the rod, as you monitor what is happening.

When all done, close up the flap, and seal with tape, long term metal HVAC tape seems the best.

Good Luck

[Texasbassman]

Hello All,

Thanks for your input. The dealership where I purchased recommended I all Good Sam Tech Support, since they gave me a 3-year Elite membership. I did call and the tech wasn't real familiar with my model, as I guess the Seismic 3815 is new within the last couple years.

We had a bad cold spell here in TX and I waited until it warmed up. The tech asked me about the sewer drain and if there were two drains. He was right! Near the rear, close to the power connection, there was another sewer drain. When I first check, it was frozen. After things thawed out, I was able to connect to it and drain the Gray 2 tank. I guess what was confusing to me was that just in front of the first axle were two pull valves, just like those on the black and gray water tanks. Those two were the low point and fresh water tank drains. I searched YouTube and the Owner's Manual and there wasn't anything about the drain setup on this RV. I will reach out to an avid "How To" RV video guy and see if he can make some new video.

Thanks again!!

2021 Jayco Seismic 3815
2019 RAM 3500 DRW 4x4 LB