Black tank Flush not working

[tomJerram]

we have a 2013 3625 RE. The black tank flush is not putting water into the black tank. I have removed the black tank check valve under the sink and replaced it with 2 elbows connected together to complete the circuit. But, still no black tank flush.

Any Ideas?

[DQDick]

The sprayer in the tank it'self may be clogged and short of dropping the belly and dealing with it I don't have any good ideas to fix it.

[DutchmenSport]

I would sooner believe the anti-syphon valve is clogged. No, you cannot blow them out or unclog them. You can only replace them.

Somewhere down-stream from the port where you attach the garden hose you'll find a valve that looks like this: Click here. Even a tiny speck of dirt can clock it up. Any RV dealership will have them.

It should be located very close to the black tank water hose connection, inside the camper.

[tomJerram]

I removed and piped around it. Still no good

[BB_TX]

Is there a check valve at the hose connection in the convenience center? May be stuck closed.

[Leftie Canuk]

Originally Posted by BB_TX

Is there a check valve at the hose connection in the convenience center? May be stuck closer.

I have a 2011 3150RL in which I replaced the anti-siphon valve, and eventually had to also replace the black tank hose connection that has the built-in check valve. The stock one would not open properly and leaked, so it was replaced. Unfortunately, this one is not ideal - I recommend checking out the various posts on this forum for suggestions on a proper brass inlet fitting with built-in check valve. If that doesn't do it, the replacement of the actual sprayer in the tank is next, I suspect. It's not that difficult, if you are okay with dropping the belly material. It's an opportunity to see how things are looking, where the key "bits' are mounted, and how Keystone does things.

[jeffba]

can the anti siphon valve be put in backwards?

[Leftie Canuk]

I tried to install mine correctly, so I blew into it to ensure I knew which side was the inlet side. So, based on my experience, I believe it is possible to install it backwards. I could see that occurring in the factory, as the time limit on sticking in the anti-siphon valve is probably measured in milliseconds.

Take a minute and test yours for the inlet side. The problems you are experiencing could be nothing more than an incorrect installation the anti-siphon valve, or even an assembly error of the black tank flusher connection fitting.

A closing thought - don't eliminate the anti-siphon valve. They are mandated for a valid risk element, and despite opinions expressed in this forum, many jurisdictions are still requiring this function to be installed in domestic water systems. For the minimal cost of maintaining the anti-siphon capability in the black tank flushing system, I urge all to continue its use.

[mtlakejim]

Folks he removed the Anti Siphon valve and replaced it with open pipe. that's not the issue.
I would go with Dicks diagnoses. It may be the jets in the tank itself that are clogged.


But I would check to make sure that there is not a check valve on the hose connection. The check valves they use for fresh water and the winterization ports are really cheap plastic that don't allow good flow at all. I removed them all and replaced with good metal ones (except for the black tank flush which doesn't have a check on it at all now to allow for max flow. I know what I am doing and won't allow backflow of nasty water into the fresh water system (the government tries to prevent this highly unlikely problem with stupid regulations which as is the case with most things the government gets involved with keeps the original function from working). It's sorta like the anti spill gas can nozzles that end up making you spill more fuel or not being able to get the gas out of the can.......

[ChuckS]

I don’t even use the black tank built in flush port. I use the Valtera clear connection with gate valve and wash port.. all 3 tanks are always clean. Much better way to clean tanks and no worries about check valves or anti siphon valve leaks.

I can physically see when my tanks are clean... all 3 tank level indicators function properly ...

[tomJerram]

I think you guessed it. There is no check valve and I have piped around the anti syphon valve. What do you think of the idea of using a compressor to try to blow out the line and sprayer?

[jcurtis934]

Using compressed air is not the safest thing to do since you could blow the hose connection on the nozzle at the front of the tank and then it could decide to leak into the underbelly. If you do this, I would drop the coroplast, raise the front of the trailer so that contents of the black tank are well back from the spray port and then start with low psi.

[Daryles]

Originally Posted by tomJerram

I think you guessed it. There is no check valve and I have piped around the anti syphon valve. What do you think of the idea of using a compressor to try to blow out the line and sprayer?

If you can pull the white PEX pipe that leads to the flusher, outside the bathroom cabinet, and connect a funnel to it, then pour boiling vinegar down into the pipe to the flusher. That might be enough th dissolve the blockage. Maybe leave it overnight.
If that doesn't work I work I would follow the vinegar with your compressed air idea. I think once the vinegar gets going it will cut through the remaining blockage.

[beeje]

Originally Posted by tomJerram

I think you guessed it. There is no check valve and I have piped around the anti syphon valve. What do you think of the idea of using a compressor to try to blow out the line and sprayer?

You can try that. I blow my line out when winterizing. I can hear air going into the tank.

[tomJerram]

I think Ill stick to just running a hose thru the toilet and use the valtra hose connection to the elbow fitting.

Thanks for your help/

[rohrmann]

There isn't a check valve in the hose water inlet for the flusher. If there is one there, it was installed in error. I was wondering if the flusher ever was used prior to this? This is a photo of where the flusher fitting is installed on the opposite end of the black tank, and on ours, it's at the front of the tank as the drain is at the rear end of the tank.

[tomJerram]

I don't think I want to drop the underbelly to get at it. But, Thanks for the info.

[Razahoryin]

I seen another previous post..
Mine is inop as well
Definitely the in tank spray nozzle...

Remove it clean it with a small drill..
Reinstall using marine grade sealants...

I’ll be doing mine next month..
I can access with only partial removal of coroplast..
I will also by pass the anti siphon valve behind shower and install a redundant back flow preventor
The anti siphon system is garbage and prone to fail.

[cgeis48]

Buy some enzyme-based black tank treatment. It is all I use in my black tank and I have never had a problem because it liquefies everything and keeps things flowing. At Amazon, it's Unique RV-Digest Holding Tank treatment. $15.99/quart. Just follow the directions on the bottle. Make it all you use from now on.

[jimcol]

If the RV is where you can do this I would try a soak using cgeis48 enzyme additive. Fill the tank with enough water to cover the flusher, add the enzyme, and let it soak as long as you can. Days if possible. If the RV is just sitting anyway it's certainly worth a try before having to drop the belly covering and removing flusher from tank.