Author Topic: Off Grid Design, Multiple Pumps, Multiple Destinations.  (Read 89 times)


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Off Grid Design, Multiple Pumps, Multiple Destinations.
« on: August 29, 2020, 04:52:43 PM »
Hi Folks,

I'm working on an interesting setup and wanted to get some thoughts from the experienced type. 

First: my water supply(working great) is a 640' deep well with a pump that sends water to a tank that resides at about 690'.  I have this pump on a aux relay that turns on a control circuit only when my batteries are charged.   When low float and high float switches in the tank are closed and this control circuit is live(batteries charged) the well pump turns on.  The tank holds about 400gal and is full after an hour of pumping.  We are using about 400 gal a week.  This is working very well!!   I can manually turn on the pump if batts are dead and I'm running on the gen.

Now for this project - Improve House Pressure AND add a new shop that is about 1300 ft away and ~50' higher.

  • The Shop Needs Enough Pressure for Shower, Toilets and a Kitchen
  • House Pressure should not exceed 60psi
  • Power use needs to be minimized
  • The pump needs to be shutoff when there is no water OR can safetly run dry
  • we need enough pressure in the pumphouse to push through a whole house water filter system.
  • flow in the house and the shop needs to be sufficient for normal household use (at least 1 gpm from any faucet)

New Parts currently on hand (If not used will sell)
  • Tank Tee
  • Square D Pumptrol Pressure Switch set to 30/50
  • 0-100 Pressure Guage
  • 70 psi pressure relief valve
  • 119 gal pressure tank
  • CSV1A
  • Cycle Sensor Pump Monitor

Power Availability:
I can use 115v or 230v (60Hz Pure Sign) or 48v direct from batt(not preferred)

Currently The tank gravity feeds to a pump control shed about 6 feet below it.  The house is about 15 feet below that.  So we have close to 9psi in the house (depending on where you are in the house).

The shop is about 50 ft above the shed.. Between PL and FL I calculated ~25psi.

Currently the plan(unless convinced otherwise) is to use 1-3gpm diaphram pumps that are commonly found for RV usage.  Preferably these will be 220v or 115v models (in order of preference).  Most of these can run dry and some are rated for continuous duty.  They usually are configured to turn on/off at pressures, some can be adjusted, and maybe the pressure switch on the pump can be bypassed.

I plan on pulling water from the one water tank with 2 pumps in the shed.  The second pump will be to produce more flow when one is not sufficient. I plan on boosting shop water pressure with a 3rd pump at the shop location.  The shop is on a different but comparable power system.

So this looks like this:

(2 diaphram pumps in parallel -> house(45+10 psi)
                                            \-> shop(45-25 psi) -> sm pressure tank -> 1 diaphram pump for boost -> shop

I have lots of questions on this.  Does this make sense?
Does it make sense to use any of the parts i have for this?  I.e. add CSV, add large pressure tank to provide more supply for shop/shed?

Thanks for your help!



Cary Austin

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Re: Off Grid Design, Multiple Pumps, Multiple Destinations.
« Reply #1 on: August 31, 2020, 08:06:41 AM »
You cannot use a CSV with a diaphragm style RV pump.  I don't think they make those little pumps that will produce enough pressure for what you want.  To add the 25 PSI for elevation to the 50 PSI needed for a good shower, you will need a pump that can work with a 65/85 pressure switch.  A submersible in the storage tank would give you better pressure for less horsepower.  The Grundfos SQ has a soft start feature which works good on batteries and will work with a CSV as well.