8285 WS black tank under pressure

Hoo Dad · 08-08-2011, 11:38 AM

Hello All,
Recently and only occasionally when the toilet is flushed the black tank appears to be under pressure and will slightly blow back. Also when removing the black/gray tank cap the line is pressurized. I currently have the camper at the dealer and the service rep hasn't been able to find the problem. My question is... where is the vent and wouldn't this be the problem (blocked)? Any one else ever have this problem?
Thanks

DAISY BOYKIN · 08-08-2011, 11:51 AM

Hummmmmm, sounds like some body forgot to hook up the vent pipe. Or may a little Pepto Bismol is needed

Aw shucks, we are just trying to get you to smile?

Hoo Dad · 08-09-2011, 10:07 AM

That's OK, I was smiling when I submitted this thread. I knew somebody would have fun with it.

Anyway, hopefully the vent is attached to the tank. That will be easy to test. If anyone is interested I'll report the poop (result).

DAISY BOYKIN · 08-09-2011, 10:49 AM

By all mean, give us a report on pressurized POOP! Sound interesting on this end.

Just curious if the vent is hooked up?

cfsoistman · 08-09-2011, 11:46 AM

When you open the dump valve does the tank drain very slowly? Vent may be tied in the tank but could have slipped to the bottom. Most black tanks are not real tall so the vent pipe might be resting on the bottom of the tank below the waste level line. I'd check the vent cap for debris as well.

DF5.4 · 08-09-2011, 02:55 PM

I thought I read that there is a check valve in the vent. If this is true and if it is installed wrong it will allow pressure to build when everything is closed.

lindy · 08-10-2011, 10:03 AM

Pressurized poop tank GREAT IDEA would make draining the tank a whole lot faster and a more complete flush.

youroo · 08-10-2011, 02:00 PM

No check valve in the stack vent. Pipe has slipped down to bottom,or not drilled out in the tank fitting. Run tank 1/2 full of water,open toilet valve,low air pressure to the roof vent,you should (not) hear water bubbling in the tank. Youroo!!

Gregad · 08-12-2011, 05:57 AM

Definitely a restriction in the vent pipe. We had a similar problem on our old FW. Yellow jackets had built a hive in the vent stack. I removed it but problem still there. Dropped a heavy fishing weight on a string down the vent pipe and found another hive had fell down in further. I had another person listen under the holding tank for the weight to hit the bottom so I knew the weight was all the way through the pipe. Now works great.

**Herk7769** · 08-12-2011, 07:04 AM

Quote:

Originally Posted by Gregad

Definitely a restriction in the vent pipe. We had a similar problem on our old FW. Yellow jackets had built a hive in the vent stack. I removed it but problem still there. Dropped a heavy fishing weight on a string down the vent pipe and found another hive had fell down in further. I had another person listen under the holding tank for the weight to hit the bottom so I knew the weight was all the way through the pipe. Now works great.

This was my thought as well. Remove vent cap on roof (watch out for ticked off bees) and probe with length of Romex (http://www.southwire.com/ProductCata...tsheet6) house wire.

The wire will bend in the pipe but stay stiff enough to punch holes through the nest. You might want to spray a can or two of wasp killer into the pipe first if you see bees in the area of the pipe.

Hoo Dad · 08-23-2011, 07:22 PM

The dealer could not find a problem and all seems OK. I spoke with Forest River and there is no check valve. They thought that the vent pipe may need to be shortened slightly as the vent cap may be resting on top of the pipe thus preventing the tank from venting. I think something may have been blocking the vent line and somehow dislodged. Anyway, it turned out to be a fun topic for disflushing uh uh discussion.

Thanks for all the suggestions.

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