No tanks

[timdenchanter]

The black tank on our 2007 3475RLS is leaking again. It has already been replaced twice at considerable expense. I was wondering why we even need a holding tank since we never stay at any campsite that does not have full hookups. After all, we don’t have a holding tank under our stick house so I was thinking I could simply remove the black tank and replace it with a p-trap beneath the toilet. An appropriately sized pipe would connect the trap to the discharge valve. When camping, we would leave the valve open and keep the p-trap filled with water.

I realize this is a totally absurd idea but so was paying $50K for this rig in the first place.

Would anyone care to tell me why my absurd idea won’t work?

[beeje]

My guess is that you are letting the tank get too full. These tanks are known to fail from being over filled. But back to your idea, sounds doable. The only issue I can think of off the top of my head is that there would not be enough water pressure/volume to flush the solids down through the trap.

[BB_TX]

I think the only way that would work well would be to install a home style tank toilet to get adequate water flow to clear all solids thru out the length of the pipe. That type toilet has a built in p trap of sort. Then you would have to be sure to drain the toilet tank before travel to avoid water sloshing out.

[MARK A]

Your toilet has a feature that serves the purpose of the p trap. Your toilet holds a little water as a barrier to gases, but I can see an issue in cold weather for the possibility of turd sickles.

Mark

[rohrmann]

I think a bigger question is, why, after replacing tanks twice, didn’t someone add supports under those tanks to prevent future failures. I had a cracked gray tank a while back, and after repairing the crack, I added additional braces across under the tanks and installed blocking between the braces and tanks, and since then, even when full, the tanks don’t sag and I don’t worry about how full the tanks are.

[jeffba]

Bob can you find the thread where you posted pix of your added supports? I was going to post it but cracked gray tank yields a ton of hits.

[karen.morgan@morrisbb.net]

We had the same problem last year with our Carriage black tank. The crack was at the top of the tank and so my husband took it out, cleaned it and took it to a body shop. They repaired it and when my husband put it back in, he added several additional braces and that fixed it.

[1retired06]

Originally Posted by BB_TX

I think the only way that would work well would be to install a home style tank toilet to get adequate water flow to clear all solids thru out the length of the pipe. That type toilet has a built in p trap of sort. Then you would have to be sure to drain the toilet tank before travel to avoid water sloshing out.

Exactly. Otherwise nasty backup.

[rohrmann]

This is the thread with photos and description of the repair and addition of braces to support the gray and black tanks that I did:


http://www.montanaowners.com/forums/...78088#poststop