Originally Posted by Iceni John
... I know that most RV-specific plumbing is not necessarily the finest quality, but what else can one use for the 3" dump valves?
PVC BALL VALVES!!!!! We have used them in weather that freezes.with no problems. I'm sure they will freeze up because the "ball" has a hole thru it and when turned off it traps some liquid inside the "hole". But our valves will be inside a heated box along with the tank. We've torn our gate valves apart on our Class C once for the black tank (rubber inside the valve messed up... yuk) and the grey valves twice, not counting when we replaced the valves. You can buy ball valves up to 4" (we have found them that large in ACE). They were very popular on the farms down in Cordele where they had the big overhead irrigation systems (water was pumped out of the river for the cotton and watermelons crops). We will plumb in a permanent black tank macerator (with a bypass) and drop all drains down to 1 1/2" to 2". We used to tent camp (7 years) and then in a pop-up (19 years) with a portipotti. When you are dumping a portipotti, you can't help but notice the "size" of stuff flowing out into wherever you are dumping it (we generally dumped into a toilet). This is why we believe we would have no problems using a 1 1/2" to 2" drain line/hose for our black tank.
... I wonder what a psychoanalyst would make of this obsession with matters excremental that most of us converters spend way too much time thinking about?
Converters seem to spend less time on Black water matters (and Toilet Paper) than the RVer's do. RVer's devote a lot of time to what is the best TP to use, to use chems or not, how often to dump... and that's not taking into account the "grey water issues" and they do have issues with grey water dumping. They would "kill" Mr Blank for dumping grey water out his front door. Which I wouldn't advise anyway. Some states (mostly eastern) will kick you off the land (I'm talking public campgrounds and dispersed camping) and will add your name to a list to prohibit you from camping on their lands in your lifetime. Southeastern campgrounds/lands are used year rounds and used heavily. Unless in a severe drought (like the last one that lasted 7 years) you cannot dump grey water on the ground (shower water is grey water) and even in a drought you can only dribble it out onto a tree or shrub if the rangers say.
BTW, this is similar to our shower pan (we found ours - used - for $25 on Craigslist and we were offered one for free last week. I don't think anyone here lives anywhere near us so we turned it down). The 32X32 will be okay but our current shower (we have a 27X48 with EVERYTHING in it combo bathroom) is small and very tight on space... "Elbow" space is 27X36.. floor space is 27X14. David complains but he uses it (no choice). Before you decide on a very small shower, mock up the size and take a pretend shower. Don't forget to pretend to wash your feet and drop the soap while you are at it!
This is what we will be using on the sinks and shower for the "P"traps. We had one in our pop up and we liked it (the big odd shaped part is the "p" trap... it's more like a air admittance valve but for water... we will try to find other uses for the rest of the fittings). I've seen them cheaper on amazon than what the link below has but you need to watch the shipping. Or you can buy a European one (cost $25 plus shipping) that uses the same technology but it's NEW and EUROPEAN so the RV lot like it. Me, I'm cheap and I've also had a lot of experience with the Camco one (19 years)