Silicone Hose for P-Trap and Shower Drain Arm??

[A_Bus_Called_Quest]

Skoolie Fam!
It's almost that time - plumbing time

Looking at where our shower drain lands in relation to the wheel well and frame of our bus - its going to be a pretty tight / perfect squeeze.

Question: Is it crazy to use silicone hose instead of PVC for the p-trap and drain arm?

I was thinking about using 2" silicone cooling hose - or something similar - to help me get the p-trap and drain to bend around the frame just right. I was thinking this would be:
A) easier than puzzling the PVC together,
B) maybe more vibration-resistant as a bonus,
C) the drain runs right next to the muffler, so I'm thinking the silicone will be more heat / impact resistant than PVC

As a backup question - I have a TON of 1" silicone hose - would it be ill-advised to reduce the shower from a 2" drain in the floor to a 1" drain arm to the grey tank? Just trying to reduce (the strain on my wallet,) reuse, and recycle!

I can try to take some pictures of my drain location - but it's pretty cramped under the bus so I'm not sure they would help haha.

As always - your time and knowledge is much appreciated

Edit: I know silicone hose is super expensive - that's why I'm hoping I can downsize to 1" drain arm and P-Trap after 2" floor drain.

[Danjo]

Being a purist , I’d always go with ABS or PVC. Still, I’ve found myself thinking more creatively. Still, all my plumbing is ABS, but it isn’t workout a lot of.strress to get there.

I think 1” is too small though. It’s going to clog up.

[A_Bus_Called_Quest]

Originally Posted by Danjo

Being a purist , I’d always go with ABS or PVC. Still, I’ve found myself thinking more creatively. Still, all my plumbing is ABS, but it isn’t workout a lot of.strress to get there.

I think 1” is too small though. It’s going to clog up.

Gotchya on the 1" - I was thinking that was the case. Looks like 1.5" is the smallest, but 2" standard.

Do you think flexible PVC would work / hold up against heat of muffler and impact from road debris?

Now I'm thinking something like this HEPvO valve instead of a P trap to help with the weird angle.

It is just a weird bend to go up and over the frame, then back to the tank. I think I may even be able to fit a solid p-trap, but as above, the bend over the frame will be funky for solid PVC or ABS, I would have to do some funky puzzle-piecing the angle joints to get it up and over just right.

[rossvtaylor]

I would definitely lean towards the Hepvo Valve! We've got P-traps in some pre-converted rigs and I remove them whenever I encounter them. On the road, and especially off the beaten path, they can slosh and if enough water sloshes out then gases and smells can enter the rig. And if you leave your rig alone for a while...especially in the desert...the water will evaporate and that also lets the stink through. So...even without any weird angles, I strongly recommend the Hepvos.

[A_Bus_Called_Quest]

Originally Posted by rossvtaylor

I would definitely lean towards the Hepvo Valve! We've got P-traps in some pre-converted rigs and I remove them whenever I encounter them. On the road, and especially off the beaten path, they can slosh and if enough water sloshes out then gases and smells can enter the rig. And if you leave your rig alone for a while...especially in the desert...the water will evaporate and that also lets the stink through. So...even without any weird angles, I strongly recommend the Hepvos.

Very good to know! I will go that route for our sink(s) for sure, though after getting under the bus again, I think I will need the flexible p-trap on the shower after all.
I need the drain to go down and around the horizontal frame (left to right) and then back over the I-Beam frame (runs the length of the bus) to the drain arm which will go about a foot or two back to the grey tank which will be mounted under the driver-side rear corner of the bus.

In theory, as long as the P-trap is below the shower floor, leading to a drain arm that is below the shower floor with a 4° slope down to the tank . . . i should be good. . . right?

I've attached some sketches - maybe that helps??? Not my best work. . . I'll get under and get some photos going as well.

[rossvtaylor]

Your artwork is just fine, BG...and that makes sense and, yes, should work as you've described it. I like that you incorporated the slope to the tank.

[A_Bus_Called_Quest]

Right on thank you! Feeling much more confident after banging my head against the muffler all day.
Now let's just cross our fingers that I can pull off the custom shower pan [emoji38]

[ttee]

I used silicone vacuum tubing in my first build. So long as you can keep it from kinking it should work fine.

[A_Bus_Called_Quest]

Originally Posted by ttee

I used silicone vacuum tubing in my first build. So long as you can keep it from kinking it should work fine.

Thank you Ttee! What diameter did you use? I think due to price I'll be using ABS / Flexible ABS couplings to help with the weird bends. . . would be so much easier with a silicone U-joint and about 1 foot of straight tube, but it is so expensive for 1.5" or 2"!

[ttee]

Originally Posted by Bear Gerschafer

Thank you Ttee! What diameter did you use? I think due to price I'll be using ABS / Flexible ABS couplings to help with the weird bends. . . would be so much easier with a silicone U-joint and about 1 foot of straight tube, but it is so expensive for 1.5" or 2"!

I used 10mm, 40 psi rated vacuum tubing for the pressurized side of my water pump. I used 6mm ID 8mm OD tubing for the water tank to water pump run.

The high pressure tubing works pretty well. I used generic but nice hose clamps. I had to buy 2 kinds until I found one that bit hard enough to actually seal the line. I then used cheap brass hose barbs to connect everything up.

I used these to as a one way pressure vent for my grey water tank.

I used this to connect my sink to my grey water tank. Its a magnetic, 1 way check valve that works amazing. I have never smelled my grey water tank and this does the same thing as a P trap without taking up a ton of space. Mine just goes in a straight diagonal line from sink to grey water tank

In your case I would find a way to get a 1 way check valve in line with the shower drain instead of using a P trap.

[turf]

a ptrap is a broken pipe after its first cold winter. hepvo is a better solution in everyway.

ihave 2 on my bus, 1 inside, under the kitchen sink and 1 outside the bus under the shower.

i think i built this in 2013 - held strong, no problems ever. its right in front of the rear duals.

[spelahar]

Originally Posted by turf

a ptrap is a broken pipe after its first cold winter. hepvo is a better solution in everyway.

ihave 2 on my bus, 1 inside, under the kitchen sink and 1 outside the bus under the shower.

i think i built this in 2013 - held strong, no problems ever. its right in front of the rear duals.

Thank you for sharing!

[o1marc]

Originally Posted by ttee

In your case I would find a way to get a 1 way check valve in line with the shower drain instead of using a P trap.

That would be the HepVo valve being discussed.



[URL=https://app.photobucket.com/u/o1racing03/p/211e8a76-dfaa-4d82-9552-71e5e5d3e2c3][/UR

[A_Bus_Called_Quest]

To all those thst helped out on this thread, I got the plumbing in! Talk about a perfect fit!
Would not have been possible without the hepvo valve.
2" shower drain reduced to 1.5" through Hepvo to greywater tank, sneaking rifht behind the muffler.
I'm wrapping the muffler in fiberglass heat shield ribbon to help with heat against the plumbing.

Thanks for all the help on this one!!

[Iceni John]

It seems to me that most bus conversion plumbing systems are unnecessarily complicated! I realized that running the drain lines under the frame rails is effectively the same as having P-traps, and that using house-size pipes is overkill, so my approach is different. Each of the five items that needs to drain to the grey tank uses 1" reinforced vinyl tube that dips under the frame rails and up to feed into a drain manifold between the frame rails that slopes down to the grey tank. I have no P-traps, AAVs, vents, check valves, etc etc, and everything drains just fine. No gurgling, no hickups, no slow draining - what's not to like? Even the shower drains just fine, and its shower pan is only a few inches higher than the drain manifold. Each drain line is an unbroken length of vinyl tube that's secured with two stainless hose clamps at each end to its nylon hose barbs. I anticipate a long and reliable life to my drain system, and if anything ever needs any attention it's easy to disconnect individual lines.

KISS.

John

[ol trunt]

"- what's not to like?" ICE.
Jack

[Iceni John]

Originally Posted by ol trunt

"- what's not to like?" ICE.
Jack

Don't worry, they're all inside the underfloor storage bays, not directly exposed to the outside air. I've thought of either using a 2kw Chinese diesel air heater (the small one) as a storage bay heater if it were cold, or just wrapping them in heat tape. Ideally though, if it's that cold I'm driving to somewhere warmer!

John