Black tank flush

[14george]

Originally Posted by SchafferFamily

So, newbie question here. What does this valve do in the first place? By removing it and making a regular elbow there, what feature are we taking away or risk are we taking on? seems to be a common issue that is posted in the searches. Even replacing it with a brass one by some members.

I'm picking up our new Passport this saturday, and I"m going to see if we have a tank flush system or not, but if I do I don't want to risk having a leak inside the new camper. I've got plenty of PEX supplies, since we remodeled our house and I"m handy, so I'm not worried about doing it myself.

valve to prevent back flow. Mine located under bathroom sink Face down has a picture of it in this post

[SchafferFamily]

Right,... so if we remove it, and if our water valve is near the same elevation as our hookup for the hose, I guess potentially there could be a chance of this line having some black water in it, at least up the one vertical side under the sink?

I guess it is more important to maintain the high elevation of the elbow to keep that point higher than the black water tank entirely.

(Looking at diagram in Post #6)

[Face Down]

From what I understand it is installed to keep a siphon situation from happening and sending contamination back into the water system ....but it seems to me this is very unlikely. For this to happen...

1. Your black tank would need to be full up to where the spray nozzle is located.
2. With the tank full, a hose hooked up to the Flush System
3. All valves on the water system open
4. Water system loses all pressure
5. Then and only then, could a siphon happen.

Since I only use the spray system once the tank is empty and open...it could could not happen with what my procedure is for flushing the tanks.

[SteveC7010]

Originally Posted by SchafferFamily

Right,... so if we remove it, and if our water valve is near the same elevation as our hookup for the hose, I guess potentially there could be a chance of this line having some black water in it, at least up the one vertical side under the sink?

I guess it is more important to maintain the high elevation of the elbow to keep that point higher than the black water tank entirely.

(Looking at diagram in Post #6)

The height alone is not enough. Remember this is an anti-siphon device. Under the right conditions, the nasty stuff can still back feed through this line without the vacuum breaker in place.

You're better off to see if you have a problem first. If you decide to remove the vacuum breaker, use an anti-siphon hose bib on your garden hose where you attach it to the flush inlet. I got several of them with various aftermarket RV accessories for flushing waste lines. If you don't have one, they're cheap and readily available at home improvement centers and hardware stores: http://www.homedepot.com/p/Orbit-Hos...7750/203720437

More info: If your vacuum breaker is brass, the chances of it failing are much slimmer that with the plastic ones. That would definitely fall into the "if it's not broke, don't fix it" category.

Folks forget to winterize the the black tank flush which could leave water in the vacuum breaker. When it freezes, it may break the plastic ones. Brass, not so much. I have an air to garden hose fitting and use it to blow out the black tank flush in the fall. It's not easy to pump the pink stuff up there, but a blast of air is sufficient to protect it over the winter.

[SchafferFamily]

Thanks Steve. I have one of those Air connection fittings and a regulator from winterizing our popup (that didn't have a black tank, only sink and grey water).

Also, thanks everyone for the clarifications,... trying to be patient and waiting for Saturday. My wife and I are excited to move up to the new camper.

[14george]

Originally Posted by 14george

Take it to dealer sat for your help

Took it to dealer worked there?