Water / Plumbing layout... double check my work here

neoneddy · June 21, 2018, 10:37:46 AM

I've attached my extremely detailed schematic for a foggy idea of what I'm doing.

I've got 2 50 gal tanks for fresh water interconnected, plus 20 gal hot water heater so the way I I figure it, I've got almsot 120. I do have room to add an additional tank near the hot water heater if I so needed.

I have 1 100 gal black tank, although my Father-in-law (Has had a few professional coaches / country coach) mentioned having a grey tank is really nice, I'm ok with a combined tank. To alleviate grey tank anxiety I'm going to put in a grey water diverter valve, so I can dump directly to the ground if we're boondocked or something where it is ok to do that.

P-traps all around to contain any odors, might even do one after the diverter valve we talked about.

As far as the bay prep goes, I was planning to put down a 1/2 ply wood to help spread the weight out a little and provide some insulation. I looked at photos of other conversions and have seen a mix of mounting to the bare bay and others with a subfloor of sorts. This is not a full time rig, but we do plan on some freezing temp outings. I figure the hot water heater will help keep the bay a bit warm.

eagle19952 · June 21, 2018, 11:00:42 AM

over flows and spills are inevitable.

in my utility bay i have put 1x2 lath on 4" centers to put air space under everything..the bottom pan of a hot water heater will rust to nothing in 20 years> ask me how i know

air circulation beneath tanks eliminates wood rot, mold, and deterioration.

neoneddy · June 21, 2018, 11:18:36 AM

Good call there, only trouble with the hot water heater is it's 32" high, the bay is 35" tall, add some fittings and it's a tighter squeeze.

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Lee Bradley · June 21, 2018, 11:38:04 AM

You should plumb the water heater so it is very hard to use it as a water source. If it is plumbed as a source, you will end up with uncovered heating elements at some point.

I like having a grey water tank so I flush the black water from the hose with grey. Don't think you want to dump grey water on the ground, if not illegal not neighborly.

neoneddy · June 21, 2018, 11:52:58 AM

@lee Bradley, can you explain more about the hot water as a source? And how to avoid it?

On dumping grey, I mean in dispersed camping areas, not right next to someone. Run a hose to the base of some bushes or something. In all reality I don't even know if I'll plumb that part in right away, but it's a possibility.

buswarrior · June 21, 2018, 12:02:08 PM

If your combined tank matches the fresh, why bother exposing yourself to any questions, and just put the drains to the waste tank and call it a day?

Hot water tank plumbed out of the top, so it cannot accidently be drained. You will immediately burn out the element if it gets a sniff of air.

If the tank doesn't fit, sell it and get one that does.

As for freeze protection, every busnut should design for that. Where in the lower 48 do you not get a hard freeze at some point?

Happy coaching!
Buswarrior

neoneddy · June 21, 2018, 12:18:03 PM

I think everyone is getting confused, not hard with the way the translation from my mind to typing is.

The primary plan is to have all drains lead to the black tank, but have the option of diverting shower and sinks if the situation arises.

My hot water heater has input and output on top, I think I'm pretty safe then. Pressure comes from the cold input side, so if the main tanks run dry and the pump stops no more water can escape. I think the only way my hot water heater would run dry is if it go siphoned out from the hot side. I'm using the sureflo pump that doesn't allow for back flow.

Lee Bradley · June 21, 2018, 01:06:03 PM

Sounds like your should be safe. I would not count it as part of the potable water; you have 100 gallons not 120 gallons unless your at a point where you drain the water heater for water. I don't know where you plan on mounting the water heater but a failure in the supply side, below the tank, can siphon the water out of the water heater as the input tube goes to the bottom of the tank. I have a check valve on mine as it is mounted above most of the supply side.

eagle19952 · June 21, 2018, 02:11:22 PM

Quote from: neoneddy on June 21, 2018, 11:18:36 AM
Good call there, only trouble with the hot water heater is it's 32" high, the bay is 35" tall, add some fittings and it's a tighter squeeze.

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a 1x is about 5/8 inch...

good luck.

Jim Blackwood · June 25, 2018, 07:57:25 AM

Using a combined tank for black and grey works, but it's a little less than optimal for several reasons. Primarily it will limit you in terms of time between dumps. This may or may not be important to you depending on your use of the RV. Grey water may have detergent and such in it but it does not have biological waste that needs processing and as such it is much easier to dispose of and depending on local rules, laws and regulations as well as good neighbor policies, can often be run down a green water hose to a ditch or other out of the way place. It's not like you use the shower all day long. Also, there are times when you can top up your fresh water tank but a dump station is not available. Do that once with a combined tank and you are in trouble, but with a separate gray water tank you can always find a place to offload the gray water and then you are only limited by the capacity of your black water tank.

Using grey water to flush out the black water is an excellent idea, and it could even be used for flushing the black water tank. To do that you'd either have to mount the grey water tank above the black water tank or use a pump and an anti-siphon loop. You'd want to avoid any scenario where the black water could backflow into the grey water tank.

There is an endless variety of things that can be done in the fresh and waste water systems to make things more convenient, usually easier to add at this stage than later. However generally complexity leads to extra failure points which is something you usually want to avoid in a system subject to vibration and other stresses. The trick is to include what you really need and want while keeping it as simple as possible.

Lastly, water heaters do have a drain valve so it is an emergency source of fresh water. Just be sure it is turned off until properly filled and burped. Sort of a hassle to use that way and best avoided but it's nice to know about that reserve.

Jim

neoneddy · June 25, 2018, 08:29:53 AM

Jim, I agree on the seperation, I went this way on account of so many nuts saying they used a single tank just fine . I don't have everything secured down yet, but I'm mostly past the point of no return for version 1.0 . I have fittings installed, etc.

We're a family of 6, I'm trying to build for a boondocking trip, but many of our trips will be using hookups sadly (I'd much prefer relaxing on some BLM land or our own secret spots, but the kids and wife want activities... sounds like work to me). Hoping with a mix of common sense water use reduction, low flow heads on show and faucets we can stretch 100 Gal until we find a dump station. I'm honestly envisioning the combined black and grey to be mostly black use. If we're beach camping at Padre, the kids will be in the ocean everyday enough to call it a shower, we'll still bring bottled water and whatnot, so that leaves water usage and waste tank to be mostly toilet and minimal shower and wink use. We even saw the tips on using dish washing water for toilet flushing water, that was interesting to really make it stretch.

windtrader · June 25, 2018, 09:32:43 AM

My bus has both gray and black tanks. Gray outlet goes into the black with a valve controlling flow into the black. A valve on the black releases to dump. It is good for flushing but it basically acts as a single tank since there is no direct outlet of gray to dump.

On occasion the gray will fill so I release some into the black until I get to dump. This hasn't been an issue as yet since there hasn't been any need/desire to dump gray by itself. Just holding until finding fill/dump station seems to work for us.

Jim Eh. · June 25, 2018, 09:47:57 AM

Second ^

My tanks are actually "stacked". My plumbing is not yet completed but the design is pretty much cast.
Although unlike above I will have an emergency outlet to dump grey water separately but for normal use will not be ever dumping any grey water anywhere other than a dumping station. And unlike most S&S campers I will always be flushing the black water tank with the grey as the control valve between tanks will be at the opposite end from the black dump valve. I will have remote cables to operate all the valves from one location. Not sure if I can justify the fancy air operated valves found on entertainer coaches so cables will probably be the order for the day.

eagle19952 · June 25, 2018, 10:15:56 AM

2 tanks.
With a kitchen sink diverting gate valve to black.
Comes in handy.

lvmci · June 27, 2018, 11:08:00 AM

Hi Ben, my black and grey are next to each other, with a T between exiting to the hose and dump. I drain the black as much as it can then open the grey fully loaded, it rushes out the T and shoots backwards into the black tank, shut the black valve, then grey, reopen the black to empty, sometimes leave some grey in the black. Only a few showers will fill up a tank, lvmci...