side vent on gray tank??

[fargotheAS]

Hey all,

Bought someone's project and half the battle is detective work to figure out what the last owner was shooting for.

Do we think this opening on the side of the gray tank was for the 1.5" air vent/exhaust pipe to the outside? Wouldn't that limit the holding capacity?

Thanks all. In the process of figuring out what to plug up vs. what to use before I build the tank back in.

Fargo

[fargotheAS]

second photo, right side of the photo (on the side of the tank)

[Minno]

Having a drain into the holding tank or a vent out of the tank from the side will definitely limit the capacity of the tank. Plus, that can be a good spot for a blockage to form in a horizontal pipe there. We would block that hole.

Chris and Kay

[fargotheAS]

Thanks guys. Yeah, I'm gonna plug it up.

[ghaynes755]

Where is your tank dump connection? Hope that isn't it since it would leave stuff in the bottom of the tank.

[DavidsonOverlander]

Originally Posted by Minno

Having a drain into the holding tank or a vent out of the tank from the side will definitely limit the capacity of the tank. Plus, that can be a good spot for a blockage to form in a horizontal pipe there. We would block that hole.

Chris and Kay

I agree about the vent needing to be on top, but why can't something drain into a gray tank from the side? If you read Vintage Trailer Supplies Advice for Designing Custom Polyethylene Holding Tanks they state:

"Inlet fittings on gray tanks are often on top. But they can be on the side, too. It doesn’t really matter. If your inlet is on the top of the tank, you can use it as a vent as well by teeing off of the inlet pipe between the sink trap and the gray tank. If you do not have an inlet on top, you must have a separate vent on top."

As long as you have a vent on the top, a drain into the side will still work. The water will just back up into the drain a little, but its level will match the level of the tank, which will still be below the level of your drain.