Plumbing - Waste Water - Bathroom Sink Drain Waste Vent (DWV).
I had purchased some "Smooth-Bore" flexible hose from Amazon in the 1.5" size. I figured I could mate it to my 1.5" waste water tank fittings and adapt it down to the two 1.25" fittings at the bath sink and at the tank entry for the bath sink.
Went shopping the other day. I bought those grey male pipe thread (MPT) to barbed fittings used in irrigation hose, but the black poly pipe for the same job is too stiff and kind of keeps a slight bend from the manufactured coil the hose comes in. Not flexible enough for hose and not straight enough for pipe, if you know what I mean.
But I figured the barbs would fit the smooth-bore brand hose I got through Amazon. It doesn't. The barbs are slightly too big.
Since I don't have a heat gun (I know - right?), I went upstairs and got DW's Tim-The-Tool-Man's Hair Dryer/Blower that I've used before on a couple pieces of the sprinkler system at the house and even as a
TC heater in Alaska.
The smooth-bore seemed REALLY weak after heating and tore easily and STILL didn't fit the barb well or easily. So I changed plans. No barbs, no smooth-bore flexible hose. By the way, it's the same stuff I saw on my neighbors gravity fill connection, something I'm not doing so I might be sending it back.
What else? What can I use? Needs to be minimal size for restricted space availability. Needs to be big enough for good water flow - can't be rubber automotive fuel line in other words.
I don't need the strength of Schedule 40 basic household PVC pipe, but Schedule 30 PVC (rigid sprinkler/irrigation pipe) doesn't exactly come with all the typical household fittings and connections as is found in the SCH 40 stuff. ABS? How's it compare to PVC? Seems slightly lighter. Older technology. Becoming less common. More effort to match it and PVC.
How about fittings? Outside diameters are important. How will that all fit? Can I get by with 1.25"? But I couldn't find any. My town's three home centers each have their own pros and cons in what they carry. I couldn't find the 1.25" at the two I checked, no need to check the third - wastes too much shopping time when you already know the answer.
So okay I settled on the 1.5". Picked up a few pieces and went to work.
The next day when I went next door to check out the neighbor's camper lift system I saw where he used 1.25 PVC on a segment of his camper. I said, "Where did you get that?" He told me from that THIRD home center. Cripes! Oh well, partly installed - I sticking with 1.5". Probably a better choice for some household fittings too - and flow.
For better or worse the decision was made and the process begun. As it turns out - in later planning - I realized how I can use the strength of the schedule 40 to become "structurally supportive" over the fresh water tank for the step-up landing, in much the same way I used the strength of the grey tank to support the battery tray. And that was just one more dilemma I needed to work out. So it all turns out well after all.
And the ONE visible spot where my galley sink drain must enter the room (come from behind the scene) is at the bottom right of the range, and it is there I can use 1.5" COPPER for the reduced outside diameter ANYWAY! Solves another problem and adds a copper visual element. Nice!
But it all started a couple days ago when I decided to build up the regions as I went and took time off from interior furniture finishing to conclude some completion ideas at the dinette seat where the battery compartment shares space with the bathroom sink tank connection. I'm drilling a large hole in the new camper box wood at that spot and another in the bottom of the propane tank compartment so I better get the measurements right!
And part of the planning and installing and measurements include building in a 1/4" per foot slope for the drain lines. Waste water won't run uphill, not while depending on gravity it won't. And I don't have the luxury of a full household wall or floor cavity with gobs of space. Not, this has to be pretty precise!
It all starts here.
I still wanted to be able to disassemble portions of the camper for repairs, etc. without disassembling EVERYTHING so the entire plumbing build is designed with that in mind. Let's start with cutting a notch in the propane tank base board.
Then drill a 2" hole for the 1.5" SCH 40 PVC outside diameter. That leaves just a slight larger hole for caulking to go.
Here's the piece I designed to accept the inflow from the bathroom sink tailpiece, and to allow for a vent.
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I also had to determine the height of the tail piece for clearance from propane tank interference and to allow for a 90 degree bend into the drain pipe at the BACK of the compartment where the rounded shape of the tanks provide enough space to do so.
And you have to use a specific type of cement for connecting PVC and ABS. The black stuff is ABS if you didn't know and the white is PVC. I'm assuming the basin is also PVC, but now as I write this - I don't know!
Anyway we'll get the sink in later once the counter and shower surfaces are completed, but for now it was to determine height and depth sizing.
Then I went underneath and inside and located the "hole" placement for that area. It was here that I ran into another conundrum. I had planned to provide a trap here on the warm side. But I'm leaning heavy toward venting the entire battery box and so it will be cooler and the trap could freeze. But do I really need a trap at all?
A trap prevents sewer gases from entering your living space through your drains. Instead those gases hit the water trapped in the loop and travel instead up your vent system and out the roof of the RV or house. You know, those nasty methane gases that come in all varieties and mostly stem from decomposing black water, to keep it all polite.
But I don't have a black water tank. This is grey water. And I'm sorry, but I kind of like the smell of toothpaste! Hey - that's just me. No seriously, I just don't see a lot of problems coming up out of the tank, especially since we won't be hooked up to the sewer drain. We'll dump when needed, and disconnect. This ain't a full-timing it unit. And if there are odors that can't be controlled by a good tank cleaning and sanitizing, well then I'll cross that trap when I get to it.
The vent now, as ticki2 had mention before, is a little different baby. That will create a better drain flow. And that's important.
So that's the plan, let's get back to work.
If you haven't done much PVC work you might find the following useful. Make your cuts as square as possible, but don't depend on them being square. Remove the burrs with a knife. Prep the joints with a proper solvent and use the right cement. Put cement on both surfaces in a nice even coat, not too little - not too much. Slide the parts together and twist them about a quarter turn in a smooth motion then hold. Holding tight together for just a few seconds does the trick. More than three and less than 30; you'll get the feel. Then wipe the excess for a prettier job. Usually build from one fixed location toward the other end - main stack toward fixture as a general rule.
Okay - here we go.
Then I moved outside and underneath.
And then up into the propane tank compartment to finish it up.
So that leaves room up here for a two-stage propane regulator.
And room down here for metal camper corner and tie-down brackets.
There was just not very much room for mistakes. But this will work :)
