How I flush my black water tank

Dalehelman

While working on another idea involving the black / gray water vent system. It occurred to me that by placing a hose into the vent pipe I can fill the waste tanks from outside the trailer. This makes flushing those tanks simple and easy. I simply replaced the stock vent cover with an outdoor double outlet cover. That way I now have access to the vent pipe.

Nomad

Does it vent when the door is closed?

Dalehelman

Yes the door does not have an air tight seal and there is  silicone around pipe itself.

jkjenn

Now that is interesting.

Ratkity

It is interesting. So physics peeps, does that mean the gasses have an opportunity of going upwards and away instead of accumulating under the "bell" and then making their escape? 

Dalehelman

Ratkity said:

It is interesting. So physics peeps, does that mean the gasses have an opportunity of going upwards and away instead of accumulating under the "bell" and then making their escape? 

????

Sharon_is_SAM

Ratkitty, even with the original bell over the vent pipe, gases will push forward and escape.  I think having the outlet at the bottom, rather than the top prevents rain/ water from entering the vent.  I think the vent pipes are importantly for the purpose of allowing air to enter and prevent a vacuum.  I suspect there may be a concern if water accumulates in that pipe - tanks will not drain.

ericnliz

FLUSH!

Ratkity

SAM said:

Ratkitty, even with the original bell over the vent pipe, gases will push forward and escape.  I think having the outlet at the bottom, rather than the top prevents rain/ water from entering the vent.  I think the vent pipes are importantly for the purpose of allowing air to enter and prevent a vacuum.  I suspect there may be a concern if water accumulates in that pipe - tanks will not drain.

Oh... of course about the vacuum. ScottG had the schematics of the black and gray tank venting pipes using that single outlet/inlet. If the pipe is too long and butting against the bell, there'd still be enough opening for air exchange to prevent a vacuum, but perhaps some extra collection is happening for Dale? It was just a thought (pre-caffeine).

Verna

@Ratkity, put on some rubber gloves, take a cheap soft bristled brush and brush the soot off your Little Campfire logs. It quick, simple and has great results. 

Ratkity

Verna said:

@Ratkity, put on some rubber gloves, take a cheap soft bristled brush and brush the soot off your Little Campfire logs. It quick, simple and has great results. 

Gloves are a must! I used an old toothbrush. The soot just flaked right off (careful of wind direction too lol). The vermiculite idea is good because it doesn't soot, but I'd be afraid it would dump out accidentally and get everywhere.

ScottG

SAM said:

Ratkitty, even with the original bell over the vent pipe, gases will push forward and escape.  I think having the outlet at the bottom, rather than the top prevents rain/ water from entering the vent.  I think the vent pipes are importantly for the purpose of allowing air to enter and prevent a vacuum.  I suspect there may be a concern if water accumulates in that pipe - tanks will not drain.

Yep, that is correct. Waste vents serve the dual purpose of allowing stinky gases to get out, and allowing air to get in so that the draining of fixtures isn't impeded by a vacuum in the pipe.

It's unlikely enough water could accumulate in the pipe to actually block it, but it would flow into your holding tanks and fill them up faster. (This is not a concern in house plumbing, as any rain water that gets in the vent just continues out to the sewer or septic tank.)

Homebodyatheart

Ratkity my concern with vermiculite is that I believe it is a known carcinogen (the dust I think), and heating it might make things worse. Just a thought. My preference would be lava rocks or some kind of stones like river rocks.

Ratkity

@Dalehelman, just curious, if the pipe has double use for gray and black, how do you know you are flushing the correct tank? Perhaps you know the amount of fluid that should be flushing out of the black gate valve when it's open and watch the clean out. I have one of the clear attachments elbows with the hose connect and valve to flush the tanks. I like that I can see when the water is clear when I'm done cleaning.

Dalehelman

While adding water through the vent water can flow into both  tanks  primarily the black. I also use a clear elbow at the discharge point. I close gate valves for a minute to allow tank to  partially fill then flush. The best part is I can flush standing up.

Ratkity

Dalehelman said:

...

While adding water through the vent water can flow into both  tanks  primarily the black. I also use a clear elbow at the discharge point. I close gate valves for a minute to allow tank to  partially fill then flush. The best part is I can flush standing up.

I'm sorry @Dalehelman!! All I could think of was an RV potty that has a foot pedal to flush it.  

BrianZ

@Dalehelman, I mainly just wanted to thank you for this great idea.  Like many of your mods, this makes life easier with minimal effort to get installed.
Question:  I thought the idea of flushing the waste tanks was something one would do after emptying them at the dump station; however, in your last photo it appears you have the water line also connected to your city water inlet.  Why? 
Comment:  Regarding @Ratkity's question, it seems to me that based on photos of the plumbing in factory photos of partially built T@Bs, one might be able to select the tank to be filled by pushing the fill hose at least 3 ft into the pipe to deliver water to the gray tank, or only a foot or so to deliver water to both or mainly to the black tank, depending on water pressure.

Dalehelman

@BrianZ
I was at a site with full hookups

BrianZ

Oh!  Ok, now it makes sense.  Thanks.
I have only heard of "full hookups", but have never seen them.  I don't know if they even exist anywhere here in Virginia.

4ncar

BrianZ said:

Oh!  Ok, now it makes sense.  Thanks.
I have only heard of "full hookups", but have never seen them.  I don't know if they even exist anywhere here in Virginia.

We were at Swallow Falls SP in western Md. and was surprised they had full hook ups. Also, I recall staying at a “mom &pop” campground outside Shenandoah, near Elkton that had full hook ups...so...there out there, though I stumble on them rather then seek them out...  

Homebodyatheart

So @Dalehelman challenged me to mod his mod. So I did. This piece of pipe insulation stops backflow from the hose, is about 2” long and just glued in. 

stepheng

Great Idea!!

Any issue with water backing up into sink or shower drain?  I don't know how the venting is plumbed for the tanks.  Is there a vent diagram posted somewhere?  I've also seen these wands you stick down the toilet with a right-angle spray fitting to clean out the black tank.  Ever use one??

Dalehelman

I did use a wand when I was at home. Because it does give a much better Rinsing of the tank. Using the vent pipe is just quicker and easier at a dump site.

stepheng

thanks for info. Is that vent for black tank only?

Dalehelman

No it vents no it vents both gray and black. Most of the water will end up in the black tank

ScottG

@stepheng, there's a plumbing schematic posted in the "Users Manuals..." category.

The vent line drops (more or less) directly into the black tank. The gray tank is vented via the sink drain, which tees off the main vent line. That's why most of the water ends up in the black tank.

stepheng

@ScottG, Thanks for the plumbing link.