Black tank flush system

[Captain Paul]

I was dumping the black tank on my RV today and when I use the black tank flush system I was not able to get any water through. I am thinking that the check valve must be seized. In trying to save myself some time troubleshooting I was hoping someone might be able to tell me where that check valve is located?

[ATTACH]

[GMFL]

It should be behind the hose connector in the wall. Most often it’s located inside the bathroom cabinet

[majorairhead]

I read one should use the black tank flush regularly to prevent the orifices from clogging. Just a thought. And a recommendation to fill the tank and drive in an attempt to unclog them.

[uncle_bob]

Originally Posted by majorairhead

I read one should use the black tank flush regularly to prevent the orifices from clogging. Just a thought. And a recommendation to fill the tank and drive in an attempt to unclog them.

Hi

If you are going to drive around to try to "clean" the tank: toss a couple of bags of ice down the toilet along with the water before you start driving around.

Bob

[Paprika]

I've owned three different tank flushing systems. The first, a "cyclone" type with spinning nozzle that I installed on my previous RV, clogged after about a year. Its replacement, with a plain nozzle, also clogged after a year. The third, preinstalled in my 2017 Airstream--nozzle type unknown--clogged after about a year. It wasn't from disuse; I flush every time I dump, as long as there's water available--and there usually is.

I love the idea of an in-tank rinsing nozzle, but in my experience, they just don't work for very long. Several friends report similar experiences. These days I use a clear HydroFlush elbow to back-flush after dumping. It isn't quite as effective as a newly installed tank rinser, but it's a lot better than nothing... and it never clogs.

[A W Warn]

The trick to keeping the flush systems operable is to wet the nozzle often.

You might try:
Dump the tanks after camping. Then fill the tank 10 to 20 percent full with clean water and add a full 8 ounce cup of laundry detergent. Also add water softener if available. Drive home, letting the soapy water slosh around. Once home continue filling the tank 100 percent full with clean water. Let it soak till next trip. That should soften the debris in the spray nozzel.

Google GEO method for maintaining your black tank.

PS
My 20 year old flush system works fine.

[truxpin]

Cross your fingers it's the check valve... ( although , it likely not) The nozzle head itself is terribly notorious for clogging. Ours stopped working a few years back after years of routine & regular use. As "luck" would have it, our tank valves developed issues and I undertook the project myself. This allowed me to remove & replace the sprayer head that's installed on the upper side of the black tank just below where the stool is located. (only accessible when pan protection is removed)
I was surprised to find the spray head itself is a crummy plastic piece that is screwed & sealed into a small 1" hole in the tank itself. The supply side of it accepts the PEX water supply & the opposite end ( the "business" end) is just a terminating point with a handful of very small (1/16") holes for the water to build pressure & "jet" water down & into the black tank.
Anticipating a future clog again at some point in the future and not wanting to ever have to pull the belly pan again unless necessary, I drilled the spray holes in the spray head out to a respectable 1/8" and even added a few more for good measure.
The factory size of 1/16" and the limited number of original holes tells me that an Engineer designed it in the perfect world of paper & pencil ( or maybe in a digital world I guess) Problem is that even a grain of sand will clog such a small hole, God forbid you actually get a spider, ant or bee past the inlet.
With the larger holes I'm sure you lose some pressure in the head, but I'll take that any day over having to manually fill the tank to flush.

[HHPJ]

That’s why I run a in line water filter on the black flush line, help keep sand and the like out of the system.
I use Happy Camper, best stuff I have ever used to dissolve solids and keep order free... and then I run the black flush with the valve closed for five minutes (on a timer...) at least three times for a good rinse/flush of the system.

[Silvr_Bullet]

To help prevent clogs use a screen in the hose to filter debris.

[PatLee]

To A W Warn - I wonder if adding hot water with your recipe would make it more effective?

[loft47]

When filling tank to break loose any materials use some Dawn dish detergent and a cup of bleach

[guskmg]

The Airstream Service Center cleared mine with very high pressure water. The feces gets into the spray holes and hardens with time. Good pressure will unclog it.
guskmg

[Captain Paul]

Thank you all for your help. Today I used a scope to look down into the tank and locate the black water spray nozzle. It is located further up in the tank and I originally expected. I filled my black water tank all the way up with hot water and added 1 gallon of cheap vinegar. I let that sit for a an hour. Then I put a little bit of vinegar in a hose and put hot water on to the black flush fill. Wala, we’re back in business!!! I looked back in the tank with the scope and all the spray nozzles are working perfectly. Thanks again everyone!

[rmkrum]

I hope you’re planning to thoroughly disinfect that scope...

[Silvr_Bullet]

Vinegar?

[Captain Paul]

Yes vinegar. It works well for cleaning.

[Silvr_Bullet]

Originally Posted by Captain Paul

Yes vinegar. It works well for cleaning.

Wondering the effect of vinegar on gaskets also when winterizing I blow out fitting with compressed air.

[thewarden]

Originally Posted by uncle_bob

Hi

If you are going to drive around to try to "clean" the tank: toss a couple of bags of ice down the toilet along with the water before you start driving around.

Bob

Sorry, but this old wives tale does little to nothing to clean your tank. There are lots of videos out there testing this and it clearly (pun intended) doesn't work.

[uncle_bob]

Originally Posted by thewarden

Sorry, but this old wives tale does little to nothing to clean your tank. There are lots of videos out there testing this and it clearly (pun intended) doesn't work.

Hi

Also lots of videos testing it and showing that it does work ....

Bob

[Silvr_Bullet]

Probably works better on cold days