Input requested- planning the plumbing

[Paladin]

Ok, for everyone who has already been down the road.
I'm beginning to ponder the plumbing for the beast in anticipation for Spring but obviously want to minimize mistakes.  What should I make sure to do and make sure to avoid in this area? I'd like to learn from others and save some time and money if I can.
Where should I start? From the tanks??
What material should I make a manifold out of?

Mucho thanks in advance

-Dave

[RJ]

Dave -

Start with the toilet and black or grey/black tank (if only using one).  Best results is with a straight shot down from the throne to the holding tank.

Decide which baggage bin you want the tanks in - most folk use the rearmost, but that's not etched in stone.

Depending on tank configuration & capacity, fresh water tank can be placed above gray/black.  There's a good article by George Lowry about building your own tanks here:

http://users.cwnet.com/~thall/george.htm

Most folk are using PEX nowadays for the hot/cold feeds.

Schedule 40 PVC is common for grey water drains, ABS for sewage.

Schedule 80 CPVC has a better tolerance for large temperature swings than regular PVC, and withstands vibration better.  Use short nipples of this type coming off such things as the water heater, water pump, etc.  No need to attempt entire system with it, just the higher stress points.  May be "overkill" in some folk's book. . .

When using PVC or CPVC, the "hotter" the glue, the faster it sets.

Unions can be a good thing, especially when you have to take something apart to fix it.  If one leaks, usually a simple o-ring cures it.

A "Mini-Sawsall" like this one is well worth the $$$.  I found the best price on a new one was from Amazon.com  The refurbished one I bought previously lasted less than a year.  Don't forget extra blades! 

http://www.makita.com/menu.php?pg=product_det&tag=4390DW

Lots of other folk will chime in, these are just a few tips to get you started.

FWIW & HTH. . .

[Paladin]

Thanks Russ, great info.
Yep I was sort of planning on rear bay tanks, hopefully straight shot down from the thinking seat. Pex tubing where I can since I have a bunch left over from the house ( 3/4" and 1/2")
I've seen many copper manifolds on coaches.  Anyone have thoughts?? Seems like metal ball valves would be real sturdy but any concerns about copper on vibration? One ball valve per circuit? How many circuits should I plan?

As for tanks, here may be a can o worms, should I have just a black or also a gray? What is the reasoning for either argument?
For size I was sort of thinking 100 fresh??? Should I be at least equal size in black??

Should I plan on two pumps? I was sort of thinking on the 5.7 Shurflow, any other thoughts anyone?

So much to plan out!!







 

[RJ]

Dave -

Have you priced copper lately?  How good are you at "sweating" copper fittings?  High-end factory conversions use them (Marathon, etc.), makes it look real pretty. 

One valve per circuit can't hurt, may help, especially if there's a problem.

PVC ball valves are virtually indestructible, and are available with unions for removal.  Weakest part is the handle!

Rule of thumb is that waste tanks should be 125% of fresh capacity.  Room for "stuff". . .

Fresh capacity is based on how long are you going to boondock w/o hookups, and how good is Mama at taking "navy showers". . .  Electric razor??

Don't forget showerhead for outdoors, too!

Will let others debate the gray/black tank issue, also pump sizing, etc.

FWIW & HTH. . .

[Len Silva]

IMO waste tanks (separate or single - I'm not going there!) should be as large as you can make them, thus the argument for custom built plastic or plywood/fiberglass.  We often camp in state parks where there are water hookups but not sewer.  That makes the relationship between supply and waste tanks meaningless.

If you opt for separate tanks (my preference) then I think 60/40 or even 70/30 gray/black works well.  I like a small offset in the toilet connection, just don't like looking down into the tank.

On the supply side, I definitely vote for separate runs from every fixture to hot and cold manifolds.  A little more plumbing but a leaking line on a trip then becomes an inconvenience, not an emergency.  The same goes for Propane.

Len

[jjrbus]

On the black and grey lines the consensus is to use "Fernco" connectors. The black rubber connectors with screw clamps. Provides some flex and makes things easy to work on.
If useing one tank, plumb in a greywater bypass, when you are sitting in campground hooked up to sewer you do not have to dump tank everyday.
 I did not have room for 2 water pumps but pump came with quick disconnects and I carry a second pump. It is plumbed in with flexible lines so replacement is quick.
In hindsight, I would run a vent pipe from as high as possible in the line from the toilet to the black tank. Gas from the tank rises, this pipe is a place for it to collect until you flush.
Size of tanks is debateable, but you do not have to fill too large a tank, but you can always overfill too small a tank. So it is better to err on the high side.

[belfert]

One reason I didn't go with the 5.7 Shurflo is water waste.  It pumps 5.7 gallons per minute so I was afraid when using faucets and the toilets that I would use more water.  Showers are generally limited already unless the restricter is modified.  I bought a Flojet Sensor VSD because it is 4.5 GPM plus it runs on 12 volt or 24 volt.

I had some issues with my copper manifold and I ended up buying a Manabloc manifold instead.  The copper manifold was built with crimp connectors, but a number of the crimp rings leaked so I am switching to Sharkbite fittings.  The copper manifold also had some bad soldering and leaked in a spot or two.

A big part of my issues came from not testing the plumbing until the day we were leaving on the first big trip.  The copper manifold could have been fixed with some time.

[Jerry32]

I put in seperate grey and black tanks for the reason stated above that when in a park you may want to leave the grey open. I didn't see the need for a seperate water manifold as it just made for extra plumbing and wasn't needed. I did put a shutoff to all else except the throne though and it is inside the closet in the bedroom so I don't have to go out to shut it off. I tried to keep all the plumbing in one compartment so in freezing weather it can be heated easily. As for sizes of tanks it is your choice depending on your use. I did use the 12/24 volt pump and have a spare plumbed in for 12 volts. I did put a filter on the water inlet to the bus so that the fresh water is filtered even when filling the tank as there is a fill valve connected after the filter. Yes and I did put it all in the rearmost compartment. I put the black and grey tanks elevated so as to have room for a drain system in the bay want have my seweer solution hose exit the bottom of the compartment so I could have the door closed all the time . Jerry

[Jerry Liebler]

What hasn't been mentioned is plan for winterizing.  Make every thing drainable and provide for antifreeze addition.  I used no manifold with Tees to ball valves at each fixture.  I highly recommend the Surflo 5.7 GPM pump.  PEX for fresh water is as good as it gets & very easy to work with.  I agree with the thought that bigger is better for waste tank especially, that's why I have 220 gallons. I built tanks using.
http://www.gumpydog.com/bus/MC9_WIP/Plumbing/Holding_Tank_Fabrication/holding_tank_fabrication.htm
Regards
Jerry 4107 1120

[Paladin]

Yeah, I was sort of planning on using Craig's plans to build tanks. I think I asked him about it too or I intend to... ( Thank God for Gumpy's page)
There is a place locally that makes tanks and also sell the plastic but I haven't checked prices, I'm sure it's considerably higher to have them made than making my own plus I don't get to learn as I go. Then again, time is always a factor.......

Silly question maybe, do I need to move the tanks in towards the center a little on the street side so that can mount a small faucet, gloves, paper towel holder etc?  I was thinking of making a small 3 sided enclosure that could hold all of that and mounting it just inside the left rear bay door although mount the drains below bay level.

What are the thoughts on vents through the roof? A vent in the plumbing plus one in the black tank?

[kd5kfl]

Lessons learned from other peoples mistakes:

Greywater tank 20% bigger than freshwater tank. Not half the size of, 1973 Pace Arrow.

Sloped bottom on the drain tanks, in two directions. So the drain is the lowest point if the coach ends up with one corner down. So if the coach ends up off-level for a while, you dont get funky stunky sulphur smelling bacteria in the part of the tanks that can't drain.

You can buy a commercial spray nozzle for cleaning the blackwater tanks. Step on the pedal and blast the clingier contents of the tank all over the bathroom and the guy operating the nozzle. Yeah, right, buddy. If you are building your own tank from scratch, consider building a spray sytem in.

[NewbeeMC9]

Vent thru the roof, not the bay , trust me ,  try to use two vents so you can get flow.

use unions and valves, cause you will have reason to remove it if you don't

make plumbing as accessible as possible,

dry fit it and pretend with it befor you commit to it.

lay out you bus with masking tape and cardboard before you start.  check alignment with bays etc, mark tanks and wiring etc.  easier to change your mind that way

Jack Conrad had a good thread going on this, type thing

remember everything seems to affect everything on these buses. 

good luck

[TomC]

Everything on my plumbing system I would do again, but now have to use PEX.  I used QEST, but haven't had any problems with it (not to say that I won't).
130gal water tank with two Surflo quiet pumps in parallel for better flow when washing dishes and someone else is showering along with the redundancy of having two pumps.  Have 2-10gal elec water heaters straight from HD that are plumbed one into the next with the final water heater wired through the inverter for hot water going down the road.
85gal gray water (would go 120 gal next time), 45 gal black water (more than enough for a week). 
I custom made copper manifold fresh water system for both the hot and cold with separate ball valves for each usage-very glad I did that.
Have external shower from Camping World, but is very cheaply built-although no problems, is just cheap.
Used custom 36" x 36" shower pan from Kohler with the drain in one corner since my bus floor slopes where the shower stall is-works well.
My toilet is on the right side of the bus and the black water tank is in the middle of the bus with a 24" pipe with two 90 degree turns in it that works just fine-so don't stress over having to have the black water tank directly below the toilet-mine is proof positive that isn't necessary.
Keep the plumbing and everything else on the bus as simple as you can get it-use as many off the shelf items as you can-I used alot from both Camping World and Home Depot for ease of repairs just in case on the road.  Be sure to secure all lines at least every 12" from vibration.  That's perhaps why I haven't had problems with the Qest plumbing yet.  Good Luck, TomC

[Paladin]

Great info here!

'nother question.
Should I make the manifold out of 3/4" with 1/2" outlets or go 1/2" throughout?

[belfert]

I just read something on PEX that recommends running 3/8" lines from a manifold where possible so hot water arrives faster.  There is a document at www.flair-it.com written by some national plumbing association about PEX and it tells you what size lines to run to what fixtures.

I've been reading a bit about PEX as I want to put it in my next home with the price of copper these days.