Sewer Tank Flusher

[Linda P]

Hello. We have a 2012 Montana and have never used the Sewer Tank Flusher. We tried to use it today (after dumping the black tank) and ran the water for a few minutes but nothing came out. Should the water start coming out of the black tank right away or does it have to build up for a while? Thanks in advance. Linda

[DutchmenSport]

Water should start flowing right away.

If no water is running, more than likely the anti-syphon valve for the black tank flush line is either clogged or it was installed backwards. The anti-syphon valve is located, probably, under your bathroom sink. It looks like this, and this is the correct position it should be in. If that flat top is on the side, it's installed backwards.



Some folks remove the anti-syphon valve completely and just connect the two lines together. I don't advise doing that, but as a quick fix or a quick way to determine if the anti-syphon valve is bad, installed backwards, or just defective, that's a quick way to figure it out.

The purpose for the anti-syphon valve is to keep the water in the black tank from "syphoning" backwards up the line and potentially back up into the garden hose and contaminate .... who knows what. Could it ever happen without the anti-syphon valve being there? "Probably" not, but then ... anything IS possible. So, remove it to test, but definitely get a new one if the old one is bad.

[Kyle and Lisa]

You should be flushing and draining the tank at the same time, for better results.

[Linda P]

Thanks a lot for the response and photo - we'll check this out. Appreciate it! Linda

[BB_TX]

Can you hear water running when you open the water valve to the flush line? I could clearly hear mine spraying when the water was flowing. I don’t remember if the flush connection has a check valve or not. If yours has one it may be stuck. Some people have added a water flow meter to the flush connection to measure how much water goes in.

I doubt the valve is installed backward. Those valve actually have an atmospheric vent that would allow water to leak into the trailer if water flowed in reverse.

Those of us who removed that valve due to leaks added an external anti siphon valve at the flush connection port.
.

[RMcNeal]

Mine failed in the first several months. I removed it and put an anti-siphon valve on the outside. I also removed the additional PEX lines that go up under the sink and back down and made it a straight shot to the tank flusher.
Seems like it works a lot better now and I can hear it running in the tank until water fills to a certain point.
I put on a water meter so I can know exactly how much water I'm putting into the black tank when flushing. I usually put around 7 gallons of water in to start the next tank full after dumping and flushing.