Black Tank Flush with Drain Closed? Problems?

[jwcrosby]

We own a 2021 22MLE and love it. I rigged up a short hose to attach to the black tank flush connection from the adjacent spray port. There is a Caution sticker there that says, "Do not use the tank flush valve unless the tank termination valve is in the open position. Can result in an unsanitary condition leading to illness or personal injury." Is the concern here about someone absentmindedly forgetting to shut off the water and consequently overflowing the tank into the trailer? I like to add 3-4 gallons of water after I've dumped/flushed but I'd hate to blow out a seal or something like that if that's a potential problem. Using the black tank flush is a whole lot easier than carrying a 5-gallon bucket of water into the trailer and dumping it down the toilet.

Anyone else doing this? Problems?

Jerry
Sandy, OR

 

[huntr70]

Yes, that's exactly what the warning is for.

You hook it up and start putting the water in, then your neighbor comes over and starts chatting, you have a good talk and next thing you know, the black tank water is coming out of the vent on the roof.

Hasn't happened to me, but I have seen it happen....

 

[Scott'n'Wendy]

but I have seen it happen....

There's a good story for around the campfire...lol

 

[jwcrosby]

... and next thing you know, the black tank water is coming out of the vent on the roof.

I guess that's better than seeing it come out the windows!!

 

[andrewssteve]

... Is the concern here about someone absentmindedly forgetting to shut off the water and consequently overflowing the tank into the trailer? I like to add 3-4 gallons of water after I've dumped/flushed but I'd hate to blow out a seal or something like that if that's a potential problem. ...

Anyone else doing this? Problems?

I know [MENTION=331]huntr70[/MENTION] has tons of experience, but I close the valve and continue to fill for a couple of minutes all the time. Been doing it for years. Can't imagine I'd ever get distracted, because I know what would happen if I did. I just believe that more water is better when you're trying to get a good flush.

 

[huntr70]

I know [MENTION=331]huntr70[/MENTION] has tons of experience, but I close the valve and continue to fill for a couple of minutes all the time. Been doing it for years. Can't imagine I'd ever get distracted, because I know what would happen if I did. I just believe that more water is better when you're trying to get a good flush.

I do the same thing.

A buddy of mine was rinsing his one time with the valve closed and got distracted. Blank tank shower off of the roof......

 

[Ynot4me2]

I do the same thing.

A buddy of mine was rinsing his one time with the valve closed and got distracted. Blank tank shower off of the roof......

We also do the same but hopefully that neighbor won't ever distract me with a nice cold one on a warm sunny day.

 

[Ynot4me2]

We own a 2021 22MLE and love it. I rigged up a short hose to attach to the black tank flush connection from the adjacent spray port. There is a Caution sticker there that says, "Do not use the tank flush valve unless the tank termination valve is in the open position. Can result in an unsanitary condition leading to illness or personal injury." Is the concern here about someone absentmindedly forgetting to shut off the water and consequently overflowing the tank into the trailer? I like to add 3-4 gallons of water after I've dumped/flushed but I'd hate to blow out a seal or something like that if that's a potential problem. Using the black tank flush is a whole lot easier than carrying a 5-gallon bucket of water into the trailer and dumping it down the toilet.

Anyone else doing this? Problems?

Jerry
Sandy, OR

I do like your setup. What adapter did you use?

 

[ckreef]

I set a timer on my phone so if something distracts me the timer saves me.

 

[rmcrowe]

I set a timer on my phone so if something distracts me the timer saves me.

This is what I do as well. I set it for 3 minutes. I sometimes worry if water pressure is high whether I'm going to overflow... one of these days I will test with high pressure how long it takes to fill a 5 gallon bucket.... For those that do this with the gate closed, how long do you usually fill for ?

 

[jwcrosby]

I do like your setup. What adapter did you use?

I bought a 2-1/2 foot hose from Amazon (Giraffe Leader Hose Hybrid 5/8 in.x 2.5FT Extension Garden Hose, Water Hose, SwivelGrip/Heavy Duty/Lightweight/Flexible Lead-Hose) and a quick connect piece (Valterra LLC PF247007 Quick Connect Hose Adapt) and it works fine.

 

[ckreef]

This is what I do as well. I set it for 3 minutes. I sometimes worry if water pressure is high whether I'm going to overflow... one of these days I will test with high pressure how long it takes to fill a 5 gallon bucket.... For those that do this with the gate closed, how long do you usually fill for ?

I set my timer for 5 minutes and check the level. You really want to just light up the full sensor. Depending on water pressure I might give it a couple more minutes.

This is a very subjective question. Black tank size and water pressure effects the timing.

 

[jstchilln]

I just bought two water hose gallon meters and plan on using one for my black tank. I sanitized my system the other day and used one for filling the fresh water tank and was able to stop it right before it ran over.

https://www.homedepot.com/p/Orbit-Water-Flow-Meter-52212/205489792

 

[RoJoSo]

I always ask my phone to set an alarm for 3 minutes, always afraid that it could happen. I read about to many stories.
Just thought I'd share what I do.

 

[MyRVRadio]

Not only do I empty and flush our black tanks every two weeks (we have a big fifth wheel), but I also do the black flush at that time multiple times. Generally at least three.

I am a fairly easily distracted person. What I do, without fail, is set a timer on my phone. Doing a flush with the valve open is somewhat worthless. That's a "we have no liability" sticker! I run my timer, depending on water pressure, about 15 to 18 minutes, once I've emptied it the first time.

I can be inside, talking to the wife, but when she hears that timer go off, I'm out of here. Immediately. I don't listen to the rest of her sentence. I will NOT have my black tank overflow. I would just die!

I have made the mistake (and fortunately, this is the mistake to make, if any) of forgetting to close the tank valve. Meaning, I'm just running water into the tank and right back out, with no water-weight pressure flush. That's happened... three times? in the past year. Again, if you're going to make a mistake in the process, that's the one to make.

 

[Foothiller]

Once I've dumped the black tank, I've always had my wife drop a deodorant/digester down the toilet and run the toilet for a few minutes while I'm dumping the grey tanks and storing the sewer hose. Once she's done, I disconnect the water.

I use the black tank flush as designed and only once in a while - not on a 1 or 2 night stay.

 

[Xlsmle]

I have a XLS 22MLE also. I usually dont dump the black tank until after a week or so of use. When i do dump it, I first hook up the hose to the back wash, then i turn the hose on and dump the tank. Then I close the valve and open the grey tank valve and dump it. After quite a bit of time like 5-10 min. I will close the grey valve and open the black valve and check to see if Im still seeing toilet paper coming through the clear elbow attached to the end of hose connected to the dump area. If its clear, i let it drain and call it good. If not, i close the black valve and let it fill again. I wlll keep doing this until i see no toilet paper coming out. Been doing this on my trailers for years with no issues

 

[schindew]

There is a certain amount of back-pressure that comes from the black water tank that may indeed back into the faucet once the faucet is turned off. I'm not sure if its enough to cause issues but it may be. I noticed that on mine when I unscrewed the hose from the black water flush and noticed the water pushing back out...I suppose if its dirty enough it may contaminate the faucet head prior to the gasket location. Hope that helps...

 

[Thumper111]

There is a certain amount of back-pressure that comes from the black water tank that may indeed back into the faucet once the faucet is turned off. I'm not sure if its enough to cause issues but it may be. I noticed that on mine when I unscrewed the hose from the black water flush and noticed the water pushing back out...I suppose if its dirty enough it may contaminate the faucet head prior to the gasket location. Hope that helps...

The water draining out is what is supposed to happen. When you disconnect the hose the vacuum breaker opens and water drains both ways to prevent contamination, that is why you should never leave a hose connected to the flusher.

 

[ckreef]

If I dump the black tank I flush the black tank. Every time, enough said!!