Grey tank troubles

[natwwal]

Greetings, we took our new Cruiser RV - Viewfinder 22RBDS out for a shakedown weekend of camping this last weekend. We've been popup campers for 14 years and this is our first camper with 'real' plumbing. I've spent months reading/talking to travel trailer owners to make sure I understand how all the systems work.

We had a great weekend (weather wasn't the most cooperative), the camper behaved exactly as expected until the last morning. I followed the advice to close the grey tank (it had been open all weekend) first thing in the morning to collect some water for flushing out the 'stinky slinky'. Before the DW could finish her shower, water was backing up into the shower. I went outside opened the grey and it drained out quickly. Took my shower, drain backed up again. When it came time to disconnect, drained the black tank, then opened the grey and ran water in the sink/shower to make sure the hose was clean.

Brought the camper to the house last night to try to figure out what's going on. Basically what I've discovered is that when the tank is empty (emptied any remaining water into bucket) I can pour about 8 gallons into the drains (doesn't matter which one) and the shower will begin to backup. Went outside and using a bucket measured how much came out of the grey tanks, and it was about 8 gallons. Once it started draining out, the shower began draining. According to the specs of the trailer it's a 38 gallon grey tank.

Went onto the roof and checked the vent for the grey tank and it's clean (even poured water down it).

Are the baffles inside a grey tank that would cause a 38 gallon tank to only hold 8 gallons?

Any ideas

[Tincup]

Wow, to my knowledge there isn't a baffle. All of the grey drains feed into one pipe that dumps into the grey tank. The only thing I can think of is the pipe that feeds the tank somehow, was pushed down into the tank and water is being forced back up the drain. The shower is the lowest drain in the rig so that's where the back up would first appear.

Does that make any sense?

Is this a new rig or did you buy it used? If it's new, I'd take it to the dealer and let him figure it out.

[natwwal]

Tincup, I'm trying to avoid a 2 hour drive back to the dealer, seems like it should be simple.

I can't really see inside the tank, but there is a connection on the top that the plumbing connect to - don't think there is anything sticking into the tank.

The shower is definitely the low spot in the drain system.

[Montrealer]

Natwwal, exact same thing happened to a neighbor 2 weeks ago. It turns out there is a valve between the grey water piping and the grey tank, immediately upstream, and then another between the grey tank and the dumping spout. He had mistakingly closed the one "upstream" of the tank, with the same backing up problems you had. His dumping valves are immediately adjacent on each side of the dumping spout, whereas this additional valve is located further upstream.

[natwwal]

Montrealer, sorry only one valve (under the trailer) for the grey tank.

Called and talked to the dealer and he's got no good ideas, we'll be dropping it off next week so he can have a look. Hope he can fix it without having to do major de-construction of the unit.

[Tincup]

Natwwal,

It's unfortunate you have to take it to the dealer, please post what they find and what the fix is.

I read Montrealers response and was very surprised and bewildered. What is the purpose of that first valve upstream from the tank?

Don't forget to post the fix

[natwwal]

Got the camper back on Thursday night (tested the grey tank yesterday) and all is well.

According to the dealer there were two problems, one was the pipe did extend into the grey tank too far (about an inch - good call Tincup) and second there was a rise in the drain line from the low point (shower) to the elbow above the grey tank.

I dumped in 7 five gallon buckets of water into the shower and it all went into the grey tank

Looks like we're good to go for our Colorado trip in a few weeks!