Reply
 
Thread Tools Display Modes
 
Old 10-23-2019, 01:03 PM   #1
Bus Nut
 
TheHubbardBus's Avatar
 
Join Date: Apr 2019
Location: Hotzona
Posts: 564
Year: 2003
Coachwork: IC
Chassis: 3800
Engine: Navistar T444e
Rated Cap: 24
Is my grey water venting / ptrap logic sound?

Please critique this plan & let me know what you think. I'm not much of a plumbing wiz:

Our 2 sole indoor water fixtures will be a shower and a kitchen sink, located side-by-side divided by a common wall. Each will tie into a common drain pipe, which will run ~ 10' to our grey water tank.

From what I think I understand, hepvo valves ('waterless' ptraps) don't require fixture venting. So would it work to tee the sink & shower drains into the common drain pipe, put a single hepvo valve on that (under the bus below both fixtures), and then run that to the grey water tank? The tank itself would be vented to the roof using the same ID as the incoming drain pipe.

If this doesn't make sense, let me know, & I'll supply scribbles.
__________________
-Sharon & Jody
Mr Beefy Short Bus Acquisition & Build Thread
TheHubbardBus is offline   Reply With Quote
Old 10-23-2019, 01:46 PM   #2
Bus Geek
 
o1marc's Avatar
 
Join Date: Dec 2017
Location: Dawsonville, Ga.
Posts: 8,264
Year: 1999
Coachwork: Genesis
Chassis: International
Engine: DT466/3060
Rated Cap: 77
Something like this?
Redundancy using both. The Hepvo keeps the stink contained in the tank. If it's vented out the roof, the hepvo isn't needed.
I need to swap the 2 tanks, as the forward fresh tank is shorter than the gray tank. But I can get proper slope with the larger tank in back.
Attached Images
File Type: jpg IMG_20191023_133955403.jpg (48.2 KB, 18 views)
o1marc is offline   Reply With Quote
Old 10-23-2019, 02:17 PM   #3
Bus Nut
 
TheHubbardBus's Avatar
 
Join Date: Apr 2019
Location: Hotzona
Posts: 564
Year: 2003
Coachwork: IC
Chassis: 3800
Engine: Navistar T444e
Rated Cap: 24
Yep. Exactly what that.


Not sure what you mean by 'redundancy using both', though, Marc. Could you elaborate? Are you saying both a tank vent and the hepvo valve? Or a hepvo valve, tank vent, AND another vent near the fixtures?
__________________
-Sharon & Jody
Mr Beefy Short Bus Acquisition & Build Thread
TheHubbardBus is offline   Reply With Quote
Old 10-23-2019, 02:21 PM   #4
Bus Geek
 
Join Date: May 2016
Location: Eastern WA
Posts: 5,618
Year: 2002
Coachwork: Bluebird
Chassis: All American RE (A3RE)
Engine: Cummins ISC (8.3)
Rated Cap: 72
Quote:
Originally Posted by o1marc View Post
Something like this?
Redundancy using both. The Hepvo keeps the stink contained in the tank. If it's vented out the roof, the hepvo isn't needed.
I need to swap the 2 tanks, as the forward fresh tank is shorter than the gray tank. But I can get proper slope with the larger tank in back.
Even with venting through the roof, you want a P trap or hepvo. Without I you will get tank stink in your living space.

All of your tanks should be vented. The displaced air, when you add fluid, needs someplace to go. Without a vent you will likely have drains that flow slowly and a freshwater tank that takes a long time to fill.
PNW_Steve is offline   Reply With Quote
Old 10-23-2019, 02:33 PM   #5
Bus Nut
 
Join Date: Sep 2018
Posts: 717
Year: 2007
Coachwork: Thomas Built
Chassis: Minotour
Engine: Chevy Express 3500 6.6l
Quote:
Originally Posted by TheHubbardBus View Post
Please critique this plan & let me know what you think. I'm not much of a plumbing wiz:

Our 2 sole indoor water fixtures will be a shower and a kitchen sink, located side-by-side divided by a common wall. Each will tie into a common drain pipe, which will run ~ 10' to our grey water tank.

From what I think I understand, hepvo valves ('waterless' ptraps) don't require fixture venting. So would it work to tee the sink & shower drains into the common drain pipe, put a single hepvo valve on that (under the bus below both fixtures), and then run that to the grey water tank? The tank itself would be vented to the roof using the same ID as the incoming drain pipe.

If this doesn't make sense, let me know, & I'll supply scribbles.
Are you using the waterless trap due to space constraints?

Can you run 2 waste pipes and tee just at the tank? The reason I bring this up is that if there is a restriction in the pipe thereís a chance of the kitchen water coming up in the shower. 2 of those waterless traps could help prevent that to some degree since it is acting also as a backflow device more than a p-trap would. If you use the waterless trap, make sure itís accessible for service. You arenít going to be able to snake it.

For a drain to work it needs air to relieve the suction of the water running down the pipe. In the setup you are describing, the drain is the vent. 10í is a long wet vent. Iím not saying it wonít work. The volume of waste water we are working with is small. Itís just something to keep in mind when designing the system.
Danjo is offline   Reply With Quote
Old 10-23-2019, 03:01 PM   #6
Bus Nut
 
TheHubbardBus's Avatar
 
Join Date: Apr 2019
Location: Hotzona
Posts: 564
Year: 2003
Coachwork: IC
Chassis: 3800
Engine: Navistar T444e
Rated Cap: 24
Quote:
Originally Posted by Danjo View Post
Are you using the waterless trap due to space constraints?

Can you run 2 waste pipes and tee just at the tank? The reason I bring this up is that if there is a restriction in the pipe there’s a chance of the kitchen water coming up in the shower. 2 of those waterless traps could help prevent that to some degree since it is acting also as a backflow device more than a p-trap would. If you use the waterless trap, make sure it’s accessible for service. You aren’t going to be able to snake it.

For a drain to work it needs air to relieve the suction of the water running down the pipe. In the setup you are describing, the drain is the vent. 10’ is a long wet vent. I’m not saying it won’t work. The volume of waste water we are working with is small. It’s just something to keep in mind when designing the system.
Understood on all counts. No, running two pipes into the grey water tank is NOT doable. I barely have enough room for one (hence my other thread that you've been a great help on).

How about if I add an AAC vent under the sink, in-between the sink & shower?

Good point about the waterless trap & snaking. It will, fortunately, be exposed, directly below the bus flooring. And yes, it was chosen based on space/routing constraints.

The thing is, on this short bus, with air brakes, AC condensors, & everything else either already there or that I plan on adding, there's literally one path I can use to route the greywater drain without encountering significant difficulty, as well as only one place the tank can go.
__________________
-Sharon & Jody
Mr Beefy Short Bus Acquisition & Build Thread
TheHubbardBus is offline   Reply With Quote
Old 10-23-2019, 03:48 PM   #7
Bus Nut
 
Join Date: Sep 2018
Posts: 717
Year: 2007
Coachwork: Thomas Built
Chassis: Minotour
Engine: Chevy Express 3500 6.6l
Quote:
Originally Posted by TheHubbardBus View Post
Understood on all counts. No, running two pipes into the grey water tank is NOT doable. I barely have enough room for one (hence my other thread that you've been a great help on).

How about if I add an AAC vent under the sink, in-between the sink & shower?

Good point about the waterless trap & snaking. It will, fortunately, be exposed, directly below the bus flooring. And yes, it was chosen based on space/routing constraints.

The thing is, on this short bus, with air brakes, AC condensors, & everything else either already there or that I plan on adding, there's literally one path I can use to route the greywater drain without encountering significant difficulty, as well as only one place the tank can go.
I know all about space limitations. Iíve been searching parts and designing/redesigning for several weeks now. Im glad I waited. Iím definitely playing Tetris like a professional contortionist.

How much drop do you have in that 10 feet?

Can you fit a waterless trap for each drain?
Danjo is offline   Reply With Quote
Old 10-23-2019, 03:58 PM   #8
Bus Geek
 
o1marc's Avatar
 
Join Date: Dec 2017
Location: Dawsonville, Ga.
Posts: 8,264
Year: 1999
Coachwork: Genesis
Chassis: International
Engine: DT466/3060
Rated Cap: 77
Quote:
Originally Posted by TheHubbardBus View Post
Yep. Exactly what that.


Not sure what you mean by 'redundancy using both', though, Marc. Could you elaborate? Are you saying both a tank vent and the hepvo valve? Or a hepvo valve, tank vent, AND another vent near the fixtures?
No need for a Hepvo if the tank is vented out the roof. I don't have roof vent. The tank contains its smell until I drain it. Hepvo prevent back venting.
o1marc is offline   Reply With Quote
Old 10-23-2019, 04:04 PM   #9
Bus Nut
 
Join Date: Sep 2018
Posts: 717
Year: 2007
Coachwork: Thomas Built
Chassis: Minotour
Engine: Chevy Express 3500 6.6l
Quote:
Originally Posted by o1marc View Post
No need for a Hepvo if the tank is vented out the roof. I don't have roof vent. The tank contains its smell until I drain it. Hepvo prevent back venting.
You havenít vented the tank? Iím curious about tank pressure caused by temperature change and microbes.
Danjo is offline   Reply With Quote
Old 10-23-2019, 04:24 PM   #10
Bus Crazy
 
Join Date: Feb 2012
Location: Salt Lake City Utah
Posts: 1,602
Year: 2000
Chassis: Blue Bird
Engine: ISC 8.3
Quote:
Originally Posted by TheHubbardBus View Post
Understood on all counts. No, running two pipes into the grey water tank is NOT doable. I barely have enough room for one (hence my other thread that you've been a great help on).

How about if I add an AAC vent under the sink, in-between the sink & shower?

Good point about the waterless trap & snaking. It will, fortunately, be exposed, directly below the bus flooring. And yes, it was chosen based on space/routing constraints.
The ideal thing would be one Hepvo valve in the down pipe under the sink and another under the floor for the shower. Combine the two pipes downstream of the Hepvo valves with a sanitary wye or tee, then run that one pipe to the gray tank.

I really like the idea of having a Hepvo as near to the shower drain as possible because of backflow. As Danjo mentioned, kitchen water could come up at the shower. Another possibility arises if the bus is parked sloped the wrong way. The drains might work but leave some water standing in the pipe between the shower and the single Hepvo. That water could come sloshing up later when the bus is moved.

You also asked about an air admittance valve (AAV). Their sole purpose is to let air into a drain system. They can resolve a situation where the water is sometimes sucked out of a P trap. Since you don't have P traps in your plans an AAV isn't useful for you.
family wagon is offline   Reply With Quote
Old 10-23-2019, 04:29 PM   #11
Bus Geek
 
o1marc's Avatar
 
Join Date: Dec 2017
Location: Dawsonville, Ga.
Posts: 8,264
Year: 1999
Coachwork: Genesis
Chassis: International
Engine: DT466/3060
Rated Cap: 77
Quote:
Originally Posted by Danjo View Post
You havenít vented the tank? Iím curious about tank pressure caused by temperature change and microbes.
Good point. I may install a studor vent. Can vent it straight off the top of the tank or put a 90 on it and send it out the back wall of the storage bin.
Attached Images
File Type: jpg studor-air-admittance-valves-20341-64_1000.jpg (58.8 KB, 0 views)
o1marc is offline   Reply With Quote
Old 10-23-2019, 04:33 PM   #12
Bus Geek
 
o1marc's Avatar
 
Join Date: Dec 2017
Location: Dawsonville, Ga.
Posts: 8,264
Year: 1999
Coachwork: Genesis
Chassis: International
Engine: DT466/3060
Rated Cap: 77
Quote:
Originally Posted by PNW_Steve View Post
Even with venting through the roof, you want a P trap or hepvo. Without I you will get tank stink in your living space.

All of your tanks should be vented. The displaced air, when you add fluid, needs someplace to go. Without a vent you will likely have drains that flow slowly and a freshwater tank that takes a long time to fill.


I have 2 fresh tanks combined by a connection hose. Can't vent the bottom tank as it is full half the time. Fill spout has a vent for fast filling.
o1marc is offline   Reply With Quote
Old 10-23-2019, 04:44 PM   #13
Bus Nut
 
TheHubbardBus's Avatar
 
Join Date: Apr 2019
Location: Hotzona
Posts: 564
Year: 2003
Coachwork: IC
Chassis: 3800
Engine: Navistar T444e
Rated Cap: 24
Quote:
Originally Posted by family wagon View Post
The ideal thing would be one Hepvo valve in the down pipe under the sink and another under the floor for the shower. Combine the two pipes downstream of the Hepvo valves with a sanitary wye or tee, then run that one pipe to the gray tank.

I really like the idea of having a Hepvo as near to the shower drain as possible because of backflow. As Danjo mentioned, kitchen water could come up at the shower. Another possibility arises if the bus is parked sloped the wrong way. The drains might work but leave some water standing in the pipe between the shower and the single Hepvo. That water could come sloshing up later when the bus is moved.

You also asked about an air admittance valve (AAV). Their sole purpose is to let air into a drain system. They can resolve a situation where the water is sometimes sucked out of a P trap. Since you don't have P traps in your plans an AAV isn't useful for you.

Excellent. That's totally doable. Plus, between you & Danjo, I now understand the 'why' behind the 'do'. Many thanks!!
__________________
-Sharon & Jody
Mr Beefy Short Bus Acquisition & Build Thread
TheHubbardBus is offline   Reply With Quote
Old 10-23-2019, 04:53 PM   #14
Bus Nut
 
TheHubbardBus's Avatar
 
Join Date: Apr 2019
Location: Hotzona
Posts: 564
Year: 2003
Coachwork: IC
Chassis: 3800
Engine: Navistar T444e
Rated Cap: 24
Quote:
Originally Posted by Danjo View Post
I know all about space limitations. Iíve been searching parts and designing/redesigning for several weeks now. Im glad I waited. Iím definitely playing Tetris like a professional contortionist.

How much drop do you have in that 10 feet?

Can you fit a waterless trap for each drain?

As per above, yep, I can and will put one hepvo off each fixture. I can locate each pretty much right off the respective drain.

Drop... I've just eyeballed it so far, but it looks like around 2" before I start running into obstructions. That's assuming the bus is flat. Right now it's 'stink-bugging' from lack of weight, magnifying the issue. Hopefully the build takes care of that, but I have no way of knowing how much the suspension will sag.
LOL on the contortionist bit. Know exactly where you're coming from.
__________________
-Sharon & Jody
Mr Beefy Short Bus Acquisition & Build Thread
TheHubbardBus is offline   Reply With Quote
Old 10-23-2019, 05:31 PM   #15
Bus Nut
 
Drew Bru's Avatar
 
Join Date: May 2016
Location: Minnehaha Co., SD
Posts: 761
Year: 1996
Coachwork: Amtran
Chassis: International
Engine: DT466
Rated Cap: 65
Quote:
Originally Posted by Danjo View Post
You havenít vented the tank? Iím curious about tank pressure caused by temperature change and microbes.
We didn't put a vent on our grey tank, but it's "vented" by virtue of the fact that the 1 1/4" house drain dumps into a 1 1/2" hole in the top of the tank. There's a bit of a gap around the drain pipe where it penetrates the tank. This seems to be enough venting to alleviate any odors wafting into our living space (we have P traps of course) and there's no back pressure. The only issues we've encountered are that there's some splashing when we move, so our luggage compartment where the tank is located gets moist, and when we drain the tank the P-traps get emptied and the bus gets some stank. I've been meaning to add a vent in the top of the tank and seal the drain penetration with a gasket, but aside from those 2 issues there haven't been any problems.
__________________
Our Build: https://dazzlingbluebus.wordpress.com/
Drew Bru is online now   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


» Featured Campgrounds

Reviews provided by

Powered by vBadvanced CMPS v3.2.3

All times are GMT -5. The time now is 08:03 PM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
×