Journey with Confidence RV GPS App RV Trip Planner RV LIFE Campground Reviews RV Maintenance Take a Speed Test Free 7 Day Trial ×


Reply
 
Thread Tools Display Modes
 
Old 08-02-2016, 04:33 PM   #1
Bus Nut
 
Join Date: Jun 2016
Location: Garden State (rural NJ)
Posts: 378
Advice Designing Water System...

Hey folks!

I'm in the process of designing skoolie subsystems and looking for some advice. I will be full-timing and am starting out with fairly high expectations that I'm sure will be tempered...

I'm looking at four wet areas in my design: kitchen sink, bathroom sink, shower and (probably) outdoor shower/hose. Bus will be plumbed with PEX throughout. (Toilet will be of the composting variety.)

I'm including on-demand LP heating.

What is the best and/or most efficient way of designing the plumbing to bypass 12v pump(s) when hooked to shore water?

I've read that the affordable tankless LP water heaters (eccotemp, Marey, etc) are particular about water pressure. Some are installing multiple pumps; one cold, one hot?

Advantages/disadvantages to including a pressurized bladder/tank to feed the bus? How big of a bladder/tank? Requires different pump(s)?

Thanks for your feedback!

BusFiend is offline   Reply With Quote
Old 08-04-2016, 10:40 PM   #2
Bus Nut
 
Join Date: Jun 2016
Location: Garden State (rural NJ)
Posts: 378
After more research, I was able to find the following schematics. A filtration system can be added. Blackwater can be deleted if going with a composting toilet.

Basic:


Fancy:
BusFiend is offline   Reply With Quote
Old 08-05-2016, 07:58 AM   #3
New Member
 
Peter B's Avatar
 
Join Date: Aug 2016
Location: Somerset, PA
Posts: 7
Year: 1998
Coachwork: Thomas
Engine: Catepillar 3116
I like layout and may steal parts of it for my conversion. One thing I'd reconsider is a composting toilet. If you have a black water tank why go with a composting tiolet. I'd rather flush it and forget then have to deal with hauling the waste through the bus for disposal.

How big are you going to make the grey water and black water tanks?

Thanks,
Peter B
Peter B is offline   Reply With Quote
Old 08-05-2016, 11:31 AM   #4
Bus Nut
 
Join Date: Jun 2016
Location: Garden State (rural NJ)
Posts: 378
I've definitely decided on the composting toilet. I'll be full-timing and plan on dry camping at least half the time. Solar power will make food and water (supply and waste) the deciding factors on length of stay. Besides, I'm looking at a 30ish foot skoolie, which limits undercarriage space. Composting is also a much simpler system and further reduces potential "system failure". As I'll be soloing, a composting toilet will go a month or better between servicing. I also don't want to deal with possible black water tank vent odors.

Space and weight will be the limiting factors for fresh and grey tanks. Currently, I'm thinking a minimum of 100 gal for each. Fresh will go under the bed, grey beneath the chassis.

If I went with black water, it would be 30-40 gal.
BusFiend is offline   Reply With Quote
Old 08-05-2016, 11:36 AM   #5
Bus Nut
 
Join Date: Jun 2016
Location: Garden State (rural NJ)
Posts: 378
I'm still trying to determine the benefits of the expansion tank. Also wondering how to implement hot water recirculation to limit fresh water waste.
BusFiend is offline   Reply With Quote
Old 08-05-2016, 11:44 AM   #6
New Member
 
Peter B's Avatar
 
Join Date: Aug 2016
Location: Somerset, PA
Posts: 7
Year: 1998
Coachwork: Thomas
Engine: Catepillar 3116
Quote:
Originally Posted by BusFiend View Post
I'm still trying to determine the benefits of the expansion tank. Also wondering how to implement hot water recirculation to limit fresh water waste.
If you are using an instant hot water tank I'm not sure you'd need an expansion tank. You may want to just install a pulsation dampener and they are fairly small, about the size of a spray paint can.
Peter B is offline   Reply With Quote
Old 08-05-2016, 11:46 AM   #7
Bus Nut
 
Join Date: Feb 2014
Location: Cuyahoga Falls Ohio
Posts: 592
Year: 1997
Coachwork: Startrans
Chassis: Ford e-350 single wheel
Engine: 5.4 litre
Rated Cap: 12
you need a vent on the fresh water tank.
leadsled01 is offline   Reply With Quote
Old 08-05-2016, 11:56 AM   #8
Bus Nut
 
Join Date: Jun 2016
Location: Garden State (rural NJ)
Posts: 378
Quote:
Originally Posted by leadsled01 View Post
you need a vent on the fresh water tank.
Yes! All tanks must be vented.
BusFiend is offline   Reply With Quote
Old 08-05-2016, 11:59 AM   #9
Bus Nut
 
Join Date: Jun 2016
Location: Garden State (rural NJ)
Posts: 378
Quote:
Originally Posted by Peter B View Post
If you are using an instant hot water tank I'm not sure you'd need an expansion tank. You may want to just install a pulsation dampener and they are fairly small, about the size of a spray paint can.
Good point. I'll put this on the further research list.
BusFiend is offline   Reply With Quote
Old 08-05-2016, 12:06 PM   #10
Almost There
 
Join Date: Jul 2016
Posts: 98
Quote:
Originally Posted by leadsled01 View Post
you need a vent on the fresh water tank.
Why is this? And what type of vent are we talking? I have a sterilized 55 gallon plastic drum from a local ice cream factory I was going to use onboard for my freshwater, it already has a hole on top that I had planned on sealing
bread519 is offline   Reply With Quote
Old 08-05-2016, 12:30 PM   #11
Bus Nut
 
Join Date: Jun 2016
Location: Garden State (rural NJ)
Posts: 378
Tanks need to be vented to eliminate negative or positive pressure when drawing from or filling.
BusFiend is offline   Reply With Quote
Old 08-05-2016, 01:48 PM   #12
Bus Nut
 
Jolly Roger's Avatar
 
Join Date: Feb 2015
Location: North carolina
Posts: 651
Year: 1986
Coachwork: Thomas
Chassis: Ford
Engine: Detroit 8.2
Rated Cap: 60 bodies
Think of the tank and vent like this.
The tank is full of air so when you start putting water or waste in a 50-gallon(for example) you will only be able to get about 30 gallons into the tank because you are compressing the trapped air and it will create a back pressure that will stop the tank from accepting the full capacity of water/waste. A vent on a tank serves two purposes one for filling as described and for draining cause if the tank can't breathe/intake air when draining you will start getting a chugging effect like you experience when trying to pour water out of a milk jug,old style gas can or bucket with a pour spout and you will be at the dump station 3x as long waiting on your tank to drain.
The expansion tank is always a good idea in my mind but think about it like this?
Another name for an expansion type tank is a bladder type storage tank.
For example installed in this manner
If pump pressure is 65psi with a expansion/storage tank inline the pump will pressurize the storage/expansion tank (an extra 5-10 gal.) with a PRV(pressure reducing valve) installed downstream of the tank set at 50 psi.
Now the pump has to only pressurize the tank and your system feeds off of the extra 5-10 gallons of higher pressured storage.
Therefore your pump will only run full time when you are taking a long shower/tub or running a water spigot
Add an expansion/bladder type storage tank and save your pump some life and you won't have to hear everytime you get a cup and f water or fill the sink.
Just my opinion and some food for thought.
Jolly Roger is offline   Reply With Quote
Old 08-05-2016, 04:05 PM   #13
Bus Nut
 
Join Date: Jun 2016
Location: Garden State (rural NJ)
Posts: 378
Quote:
Originally Posted by Jolly Roger View Post
Just my opinion and some food for thought.
Thank you for your thorough explanation! It makes so much sense. It evens out the water pressure and flow and reduces pump wear.

Do you think a bladder/expansion tank addresses any concerns of the finicky on-demand water heaters?
BusFiend is offline   Reply With Quote
Old 08-05-2016, 06:56 PM   #14
Bus Nut
 
Join Date: Jul 2016
Posts: 543
Just thinking out of the box. A 50 gal pressure tank (fresh water) pressurized by air or city water when connected.

Sent from my SM-G530W using Tapatalk
Tootalltechie is offline   Reply With Quote
Old 08-06-2016, 09:47 AM   #15
Bus Nut
 
Jolly Roger's Avatar
 
Join Date: Feb 2015
Location: North carolina
Posts: 651
Year: 1986
Coachwork: Thomas
Chassis: Ford
Engine: Detroit 8.2
Rated Cap: 60 bodies
Depends on what the heater is picky about?
If it water flow then probably not and if it water pressure then probably not.
The pump is going to move the same amount of water whether it is doing it at 10 psi or 50 psi.
Never had an on demand heater?
To make the heater happy I would think that the piping size needs to be adhered to to give the heater proper flow.
A return line system defeats the purpose of an instantaneous heater purchase?
In my opinion
Jolly Roger is offline   Reply With Quote
Old 08-06-2016, 12:15 PM   #16
Bus Geek
 
ol trunt's Avatar
 
Join Date: Apr 2012
Location: So Cal
Posts: 3,227
Year: 1935
Coachwork: Superior
Chassis: Chevy
Engine: 317 ci/tid / Isuzu
The instant hot water heaters are only instant if they are located immediately at the spigot they serve. The further away the spigot, the more water is sent down the drain while waiting for hot water to arrive. That is no big deal if you are hooked to city water but if you are boondocking it is as many gallons of water are wasted waiting for the hot water to arrive.

Also, because instant hot water heaters require both water pressure and water flow to operate the heater cycles on and off with each cycle of the spigot. This results in a choppy mix of either too hot or too cool water at the spigot.

By utilizing an electric solenoid water valve which directs hot water flow back to the water tank you eliminate waste of water and achieve an even flow of pretty constant temperature water at the spigot regardless of its distance from the heater. If you wish maximum flow of hot water (3 gal/min in my case) switching off the solenoid valve directs all the water flow to the spigot.

In my experience water seems to be the limiting factor when it comes to boondocking so anything that can be done to conserve water use becomes important. I've yet to use up my propane supply before running out of water but I suppose it could be done if one tried hard enough. I wrapped the hot water pipes leading to the various spigots with foam insulation but left them bare on the return line to allow the water to cool before going back into the fresh water holding tank. Jack
ol trunt is offline   Reply With Quote
Old 08-06-2016, 12:38 PM   #17
Bus Geek
 
Tango's Avatar
 
Join Date: Mar 2011
Location: Houston, Texas
Posts: 8,462
Year: 1946
Coachwork: Chevrolet/Wayne
Chassis: 1- 1/2 ton
Engine: Cummins 4BT
Rated Cap: 15
Several of the folks I know who live with tankless water heaters always capture whatever cool water comes out and use it for other things. One even pours it back into his tank.
Tango is offline   Reply With Quote
Old 08-06-2016, 12:49 PM   #18
Bus Nut
 
Join Date: Jun 2016
Location: Garden State (rural NJ)
Posts: 378
Quote:
Originally Posted by Tango View Post
Several of the folks I know who live with tankless water heaters always capture whatever cool water comes out and use it for other things. One even pours it back into his tank.
As I've combed through forums, this seems to be the general solution to the problem. A few posters have briefly discussed recirculating water but never to the point of describing the system or mentioning specific equipment. I suppose for those only spending a few weeks a year in their RV, catching the cool water for other purposes is just fine. For full-timing, I would think a recirc system would be desirable.
BusFiend is offline   Reply With Quote
Old 08-06-2016, 12:52 PM   #19
Bus Nut
 
Join Date: Jun 2016
Location: Garden State (rural NJ)
Posts: 378
Quote:
Originally Posted by ol trunt View Post
In my experience water seems to be the limiting factor when it comes to boondocking so anything that can be done to conserve water use becomes important. I've yet to use up my propane supply before running out of water but I suppose it could be done if one tried hard enough. I wrapped the hot water pipes leading to the various spigots with foam insulation but left them bare on the return line to allow the water to cool before going back into the fresh water holding tank. Jack
Thanks, Jack! Agreed. This is what I was thinking of. Now to find the components and work into a system design.
BusFiend is offline   Reply With Quote
Old 08-06-2016, 01:47 PM   #20
Bus Geek
 
ol trunt's Avatar
 
Join Date: Apr 2012
Location: So Cal
Posts: 3,227
Year: 1935
Coachwork: Superior
Chassis: Chevy
Engine: 317 ci/tid / Isuzu
BF, here it is, $7:

1 2" 12 Volt DC Electric Solenoid Valve N C Plastic Body Water etc DDT CS 12VDC | eBay
ol trunt is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


» Featured Campgrounds

Reviews provided by

Powered by vBadvanced CMPS v3.2.3

All times are GMT -5. The time now is 05:10 AM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2024, vBulletin Solutions, Inc.