6x10 Hiway Cargo plumbing

[Trailmate]

Hi Y'all,
I'm a noob and this is my first post here so, please, bear with me. I've been working on my little cargo trailer and it's time to do a little plumbing. I've done some homework in preparation but the more I read, the more questions arise. I think I've got it mostly figured out but, at this point, I think it would be a good idea to get some input.

I found a good post here viewtopic.php?f=54&t=54069 that was helpful. There was discussion about Qest mechanical fittings there from 48Rob. I had some Qest plumbing in my old Newell. It had been in there for 15 years and never leaked. I liked the stuff and, after reviewing Rob's thoughts about it, I'm looking at Qest fittings https://www.plumbingsupply.com/polyb.html.

The concept for this trailer is to have it set up for shore power and water so (for now), no holding tanks and no 12V. I've got it wired for 30 amp service which I installed thanks to another post by 48Rob. Actually, it was mostly drawn from a good picture he posted of what he used. Needless to say, space is at a premium and I'm trying to get all the stuff I know I like in a trailer and that includes a toilet and sink. The toilet is a dometic 310. My plan is to install a water inlet and tee off to the toilet and sink.

The inlet I chose is stainless steel 1/2" NPT. The walls of the trailer are now 2" inches thick (fully insulated with rigid foam, 1/2" plywood walls over steel studs and 1/4" paneling). The female threads on the backside of the water inlet are only about a 1/2" deep so I'll need a nipple the correct length to protrude through the wall long enough to connect to. Does stainless pipe require pipe dope/teflon tape ? I'm thinking a 90 degree fitting on the nipple on the inside (see picture). I'm thinking 1/2" pex pipe? Then from the 90 degree fitting, connect a tee (again, if I did this right, pictured). I just tried to attach it but apparently there is a 3 pic maximum per post so I think I should try posting this and start another because I really don't have any idea what this is going to look like. My apologies in advance if it's a mess. This is my first post. So here goes!

Paul

[Trailmate]

Okay I just looked at the above post. Not too bad for a first try but the pictures looked way too big, at least on my computer. I went ahead and resized the other pics I took. They are pretty small looking so I might need a third try before I get them just right!

Let's see. Where was I? I'm going to include a couple of pics of the toilet and sink in place. The toilet will be at the foot of one of the folding beds. I know it's not in the greatest location but it's the only spot I can fit it in. So, getting back to the plumbing, with the tee installed, the left side would go to the toilet. I haven't quite figured out which one of the Qest fittings would be needed to connect to the dometic 310. The right side would go to the sink. There are two connections to the hot and cold on the faucet. It's a Price Pfister faucet. Instructions don't state size of connection but it looks like a standard faucet. I'm not sure if a Qest fitting will connect directly the the faucet thread or not so I could use some input on that too. I suppose I would also need a Qest tee to split the water input line into two for the hot and cold. I won't be running hot water but I'm thinking I would connect both left and right faucet inlets even though I'm just running cold water.

The sink drain is 1&1/2" and I think I'll need a s-trap for it. I found one at Home Depot. I'm thinking I'll be using all pvc for the drain plumbing. ABS would be nice but I don't think it's necessary. There is a lot of steel underneath the trailer to plumb around but I think I've figured out a route. I looked at a stock floor flange at Home Depot: http://www.homedepot.com/p/Sioux-Chief- ... K/20231321. Don't know yet if this will work with the Dometic 310 yet or not. This is what I came up with for the drain: http://www.homedepot.com/p/NIBCO-3-in-x ... /100678004. Those URLs are big. If the post too big, I'll have to figure out how to make them smaller. What I'm thinking is connecting the sink drain pipe to the toilet elbow via the 1&1/2" side inlet and install a bayonet fitting to the outlet of the elbow and that would be a direct sewer hookup. I don't plan on dry camping this trailer. At least not now. If I want to dry camp it I'll consider that when the time comes. For now I just want a camper I can tow over to the east coast and hook up at a state park. I'll get a portable black/gray tote tank for parks with a dump but no sewer connections. Here's an URL to the bayonet connector: http://www.amazon.com/Valterra-T1029-1- ... B002N5T4PM .
Well that's probably enough for now. I'll post this and see how it looks and if I need to make changes.

[Trailmate]

I just looked at the pics that I sized down on the second post. They look too small to me. I'll try 640X480 on my next post. I have given thought to having a toilet without it own enclosure (bathroom) in the living area with my main concern being odors not privacy. The bowl will always have water in it so that should keep out odor from the sewer connection. I'll probably be running the AC a lot here in FL so it should pull a constant supply of fresh air. I've got a roof vent installed and 2 good sized Kinro's for fresh air too. The s-trap in the sink should keep the odor down too. Here's a pic size that I think is hopefully just right:

[aggie79]

I believe the RV toilet floor flange is different than a residential closet flange.

There are a couple of items I don't see that you've mentioned. You'll need a vent stack for the sink and toilet to keep one from siphoning the other. Also, you'll need a gate valve upstream of the bayonet connection.

You can use PVC for the sink drain and vent but I'd think about using ABS from the floor flange all the way to the bayonet connection. If you mix PVC and ABS drain-waste-vent pipe you'll need to use transition fittings where the two meet.

[Trailmate]

Hi, thanks. I don't know for sure about the residential floor flange not being compatible. Guess it would be safer to just go with the rv flange. It's hard to know what your dealing with looking at pictures of it on the internet. If I could look at all this stuff in person it would be a lot easier. I was hoping to avoid having to vent the toilet and sink. I figured with such a short distance of pipe involved from the sink to the toilet, the toilet would not siphon the trap on the sink. I wanted to avoid venting. I would imagine that would involve running a pipe through the roof. I've read about air admittance valves. I'll try a little research on those. Maybe a p-trap with an air admittance valve.

I considered the gate valve. I thought, without a holding tank and the direct connection to the sewer line I wouldn't need a gate valve. There's not much room to work with under there. Perhaps for convenience and sanitation it would be better with the gate valve. I thought I'd just get a cap for the bayonet connection when not in use. I figured when disconnecting, I could just shut the water off, flush the toilet so the bowl was empty, remove the sewer hose and just put a cap on the end.

I'd prefer to use ABS and probably will. Home Depot and Lowes don't stock much ABS at all so I'd have to order that stuff. Don't know where I'd find it locally. Maybe a plumbing supply outlet. I've looked on line for local plumbing supplier. Not much to choose from around here though. I don't know what a transition fitting is. I'll try reading up on that. So that "termination adapter" (bayonet fitting) I showed the link to is ABS. I'm guessing that adapter will not slip inside of a 3" pvc elbow? If it would I figured I could just use the correct adhesive to glue abs to pvc. I have a feeling though that it won't slip inside a 3" elbow.

I forgot to attach the Qest tee that I mentioned. Let me have a go at that:

[aggie79]

I should have mentioned that I have not done any actual RV plumbing. What I relayed is what I've found out in researching a possible cargo trailer conversion. I have heard good things about the Qest fittings for water distribution.

What I've seen of your build so far, you've done a very nice job. Since I'm thinking about a CT of the same size, I would love to see more pictures about your build.

Take care,
Tom

[Trailmate]

Thanks Tom,

All the suggestions you made were essentially spot on. I figure, if anything, this thread could help not only me but anyone else here faced with the same issues. As with all threads, there will be some info that is erroneous and others will chime in to set the record straight. I will post my "build" eventually to make my contribution to the forum. I'm pretty good at figuring stuff out eventually but I must admit that trying to sort out this plumbing challenge without any of the components at hand is not only confusing but not an efficient use of time. A plumber could look at all this stuff online and know what will work but I like a challenge and I'm working through it! Yes I've had some personal experience with the Qest mechanical fittings. I found references to Qest on a search here before I became a member and 48Rob mentioned he uses them. I kinda feel that you could take just about anything that guy says about trailers to the bank. If he doesn't notice this post I'll PM him and ask for his advice.

[Trailmate]

Couple of images of the elbows I'm considering for the toilet drain. I'm thinking glue one of these to the toilet flange and then glue a bayonet fitting to the outlet of the 3 inch elbow. The sink drain pipe would connect to the inch and a half side inlet on the elbow.

[kenm8521]

Couple of images of the elbows I'm considering for the toilet drain. I'm thinking glue one of these to the toilet flange and then glue a bayonet fitting to the outlet of the 3 inch elbow. The sink drain pipe would connect to the inch and a half side inlet on the elbow.

I'm not that familiar w/ RV toilets, but IIRC, they use considerably less water than standard household toilets. This is likely going to cause an issue w/ any solids moving through your 3in pipe.

In a typical RV setup, a tank is full of solids/fluids, and the fluids help move the solids through the pipe when the gate valve is opened (leaving the gate valve open on the black tank is frowned upon for this exact reason... Google "pyramiding")... It looks like you're going to attempt to run this like a standard household toilet. I could be wrong, but I think you'll have problems doing this.

If you went w/ a standard household toilet however... it should be OK.

[Trailmate]

RV toilets are filled manually for solids so the user can fill the bowl as they see fit. This toilet will be used for solids only on an emergency basis. I'm setting this trailer up, for now, as a park model i.e. no holding tanks. The trailer was originally equipped to haul two motorcycles as it has a ramp door. I intend to retain that function. That's why I built the fold up beds.

[kenm8521]

RV toilets are filled manually for solids so the user can fill the bowl as they see fit. This toilet will be used for solids only on an emergency basis. I'm setting this trailer up, for now, as a park model i.e. no holding tanks. The trailer was originally equipped to haul two motorcycles as it has a ramp door. I intend to retain that function. That's why I built the fold up beds.

I understand it's going to only be used in a park with a sewage connection... Having done a lot of plumbing however (granted, not on RV's), I still anticipate problems with this. I guess as long as anyone understands that they have to "manually" fill the toilet w/ water before flushing, it should be ok.. but I have a feeling you're probably gonna end up regretting doing this.

[Trailmate]

Maybe. I've thought it out. I have some reservations. I'm pretty sure I'm not the first to do it. Maybe somebody with actual experience with this will chime in . I don't really anticipate anything major. RV toilet, flange, 3" elbow with a bayonet connection on the outflow. I'd be dumping liquid from the toilet through the elbow and down the sewer line. At a park without sewer hookups I'll connect a portable tote tank and dump at their dump station. Bowl of toilet will hold minimum of water at all times to keep out sewer gases.

[hankaye]

Trailmate, Howdy;

As a full-time RV resident I'll just say this, your idea has some merit to it.
In theory, Use it, fill it (for us RV'ers the axiom is water is your friend), when
the black tank is 2/3s or more full dump it. But then we have the gray tanks
contents to flush out the hose and associated run.
Now if you choose to flush (clean), the system plumbing with a hose hooked
to one of these http://www.valterra.com/product/rv-hydr ... at_id=1234
you can keep the bottom of the bowel shut and it should do the clean-out
for ya and ... you can see when the last of the nasty bits are gone.
My waste drain is 3" Black PVC as are most RVs and just do the normal PVC glue-it
to assemble. Don't forget to get a cap for when you travel.
The above link will also lead you to all the other fittings an what-nots you may need.

hank

[Trailmate]

By "black pvc" I'm guessing it is ABS. I believe most RV drain pipe is ABS ABS and pvc both have their own specific adhesives and abs can be joined to pvc with an adhesive formulated for that purpose. PVC is fairly readily available at local stores however ABS is not. I prefer ABS but haven't ruled out PVC. I'd have to order and wait for the ABS. I want a toilet in this unit. I don't want my wife wandering around a campground in the middle of the night looking for the restrooms and I'm not a fan of portapotties. I've pretty much figured out what I need for hardware though not quite there yet. I PM'd a member here for advice but haven't heard back yet. That was only a couple of days ago though. I'm sure he's got other things going on and hasn't visited the site since I messaged him. I figure a toilet with no holding tank is better than no toilet at all. If I decide I want holding tanks in the future I'll look into it. For now, I won't be dry camping. I appreciate the merits of a self contained trailer but if I were to go that route, I'd probably look into a conventional rv trailer/camper/toyhauler (motorcyle) . I've sourced the Qest fittings I need. Haven't got that part all figured out yet but I think I'm close. Kind of have the trap plumbing figured out but still have some questions there. There is very little room up front under the countertop for a trap so the most compact trap I've found is an s-trap. Apparently s-traps have their detractors. I don't want to install a stack vent for the sink if I don't have to. I plan on connecting the sink drain pipe to the toilet elbow thus the inch and a half side inlet on the elbow I posted. I have concerns about the toilet siphoning the s-trap but I don't think it would being it's such a short distance from the sink. I'm hoping somebody knowledgeable in that area could give me a definitive answer. I've thought about a Studer type vent if I have to vent the trap. I could always install it and test it afterwards but that's a chance I prefer to avoid. I'll be drilling rather large holes in my pretty tongue and groove floor so I'd like to get it all that right the first time. Haven't quite figured out how to connect the sink inlet lines with the PEX yet either.

[Trailmate]

Hank's post got me to thinkin'. If I install the elbow directly to the toilet flange and connect the sink drain pipe directly to it then I'm going to be getting some outflow from the toilet into the sink drain line. I knew that already but it didn't really occur to me how, in the long run, that could just be not good at all. I'm going to have to come up with a way to tie the sink drain to the toilet drain that would not allow that to happen. Back to the drawing board!