Venting a second gray water tank

[vannooch-HILO]

I'm researching how to add a second gray water tank to my HiLo. I have room to add another fifteen gallon tank and tap it into the inch and a half line between the knife valve and the tank. I was think of just taping it into the line to give the water somewhere else to go but that leaves me with the problem of venting it. I was considering running two lines between them but I can't get through a frame member to do so.
All of you plumbers out there, is there a gadget that will let me do this? Some new fangled gizmo that I can tap into the side of the tank? I'm thinking not, because it would have to be a two way valve that would stop water but let air pass, exhausting the air from the tank when filling and aspirating air when draining the tank all while not dumping the water onto the ground.....
I can't be so lucky to just find this engineered marvel.

I considered just running ont of the other lines from either the sink or shower into this tank but that's just a whole different can of worms.

Whatcha got?

 

[Thankful]

I'm researching how to add a second gray water tank to my HiLo. I have room to add another fifteen gallon tank and tap it into the inch and a half line between the knife valve and the tank. I was think of just taping it into the line to give the water somewhere else to go but that leaves me with the problem of venting it. I was considering running two lines between them but I can't get through a frame member to do so.
All of you plumbers out there, is there a gadget that will let me do this? Some new fangled gizmo that I can tap into the side of the tank? I'm thinking not, because it would have to be a two way valve that would stop water but let air pass, exhausting the air from the tank when filling and aspirating air when draining the tank all while not dumping the water onto the ground.....
I can't be so lucky to just find this engineered marvel.

I considered just running ont of the other lines from either the sink or shower into this tank but that's just a whole different can of worms.

Whatcha got?

vannooch


I know of no gizmo that will do what you want.

I have a few questions.
1) On the new tank, how many threaded outlets are there and where are they located?

bottom
sides- how far up on the sides-low, middle, near the top
top
2) Where is the new drain line coming from the existing drains going to enter the new tank? bottom, sides or top

Here is where my thoughts are leading me:
If you have an unused threaded outlet near the top on the new tank, I would run a hose from that outlet up into the camper to either the existing vent stack or to a drain line.

If tapping into a drain line inside the camper:
1)Make sure that it is located between the existing tank and the sink traps.
2)I would put in a tee so that the tee is facing up, so that the hose enters the tee from the top- that would help keep water and solid particles from traveling down the hose.
3) Use the largest hose possible.
4) Make sure there are no low spots in the hose for water to collect otherwise this would plug off the vent hose.
5) When tapping into the existing drain lines- If you have ABS pipes you can not glue PVC pipe to it.

If you don't have any threaded outlets near or on the top of the new tank, I will have to rethink things.

 

[PopRichie77]

There is a cleaning solvent that will let you glue ABS to PVC, got mine at either Lowes or Home Depot. A plumber told me about it, worked grate, when all the pipes were removed from under my 95 from the tread coming off the tire. Only pipes I could get at the time was PVC.
You could run a hose from the top of one tank to the top of the other.

 

[Thankful]

There is a cleaning solvent that will let you glue ABS to PVC, got mine at either Lowes or Home Depot. A plumber told me about it, worked grate, when all the pipes were removed from under my 95 from the tread coming off the tire. Only pipes I could get at the time was PVC.
You could run a hose from the top of one tank to the top of the other.

Thanks PopRichie77,

I didn't know that home depot or lowes sold the ABS to PVC transition cement. I thought they just sold the all purpose cement, which I believe is to glue ABS to ABS, CPVC to CPVC and PVC to PVC but not one to the other. I have seen many failed ABS to PVC glued connections.

 

[PopRichie77]

Just looked, it's call (All Purpose Cement) says for ABS, CPVC, PVC, it's made by Oatey #30821 and now that I think about it I am pretty sure I got it at Lowes.
Actually bumped into the plumber at Lowes, was lucky or I would have tried to use the wrong cement. Was getting some pipe and fittings and he asked what it was for and I said an RV, he knew just what was needed.

 

[Papa-HILO]

Additional Gray water tank

Vannooch,
I added an addtional 30 gal. gray water tank to my 2805C. I connected it to the drain line between the existing tank and the knife valve. I had to make sure the new tank was installed so it would line up (not above or below) the existing drain line. The tank came with one hole in it. That's what I used for the line I connected to the existing drain line. Concerning venting the tank it did not come with a vent hole. So I had to cut on and install a fitting so the tank would vent. I used all black pipe just like the existing drain pipes in the Hi Lo. Pipe and cement was all available at Lowe's. As a test I cut a very short peice of the 1 1/2 inch pipe and gluded it to the outside of the tank just to see how strong the cememt was...........it was very strong and easy to use. I was fortunate that my new tank was located in the underside bay right under the bedroom's wardrobe. I was able to drill a hole in the wardrobe floor and then run a vent pipe through the back wall of the wardrobe under the shower to the existing venting for the gray water system. I found the planning the be the hardest part of the entire job. Just had to make sure everything fit.
I have some photos should you be interested. send me your address.
God Bless
papa

 

[sting32]

Why not vent new tank to the old tank?

with even a plain old rubber hose and fittings?

are you having the add on tank be downstream and below the original? I wouldnt try that myself. I mean this would be easy and just like saddle tanks used on motorcycles, with them mounted same level, and since the dual tanks should now fill at same rate/levels? IT would eliminate having to retrofit, through the cabinetry inside the camper over to existing vent? not only that, if you keep both tanks at same level when mounting under the camper, and did 2 of the same size connectors to the tanks (between them) one high (even small hose) and one low, then you wouldnt need to have new level probes in the tank either, right, since they fill simultaneously? Im envisioning 2 pipe lines between tank, one at bottom like you do now, one at the very top. you dont have a disposal in a camper so draining grey isnt much of an issue, while I was under there you could run a hose with a Y in it, to both tanks to help flush when dumping.

And if you were doing tanks one above the other, I still believe that the same would still work, vent new lower tank to top of old tank... Only thing I see is it would be a LONG time before the 1st one above the bottom (or lower probe) tank probe is covered in original tank, then lights the panel, but then each next level would seem to fill quickly from there as you used this setup. Else you would need to distribute the probes somehow, to both tanks, and seems to me to make things complicated.

 

[vannooch-HILO]

the only place that I can mount the second tank on mine is right under the entrance door and isle into the trailer so venting out of the top is out. There are frame members all around the only place that I can mount it except there are holes through the member between the tanks. I didn't remember this but when I was under there I took some photos and saw the holes in the photos. I am tapping into the drain between the knife valve and the original tank and try to vent between the tanks through the hole in the frame. The second tank will be just an overflow tank, I researched the tank and there is one that I can buy with a side drain hole at 9" to the bottom and that is where I will tie into the existing drain line that is at 9" as well.
I wanted suggestions on venting because of the frame members surrounding the tank. Seeing the hole in the frame, I think that I have a plan. Papa, I would like to see what you have done, I will message my email to you.
Of course, I may be able to run it under the floor and up behind the drawers in the bathroom and tie it into the vent stack......
Hmmmm

 

[Papa-HILO]

Venting additional gray water tank

sting32,
I guess you've raised a way to do the venting that I did not think about when I installed my extra gray water tank. What you say should work if one could get a vent from the top of the new tank to the top of the existing tank. In my case there is a frame cross member between the two tanks. I would have had to drill a hole through the frame to run a pipe or hose from one tank to the other.
The drain pipes were another issue but they both ended up lower than the bottom of the frame member.
Good idea but it never crossed my mine. Just proves there is always more than one way to do a job. Thanks for your ideas.
God Bless
Papa

 

[Thankful]

Just looked, it's call (All Purpose Cement) says for ABS, CPVC, PVC, it's made by Oatey #30821 and now that I think about it I am pretty sure I got it at Lowes.
Actually bumped into the plumber at Lowes, was lucky or I would have tried to use the wrong cement. Was getting some pipe and fittings and he asked what it was for and I said an RV, he knew just what was needed.

PopRichie77,

I don't want to beat a dead horse but do not use the all-purpose cement to glue ABS to PVC. You need to use the green transition cement. I confirmed this with Oatey to make sure I have been doing it correctly all of these years. The all-pupose cement is for ABS to ABS, CPVC to CPVC and PVC to PVC and not one to the other. Like I stated before I have seen many failed ABS to PVC glued connections.