Is my 12V DC Aquatec booster pump not keeping up with my pressure tank?

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DesertDweller
DesertDweller Registered Users Posts: 16 ✭✭
in Solar Water Pumping #1
Hi, I've been trying to setup a solar powered well house and it's almost got all the kinks worked out but I only get about 2 gallons out of the sink before the pressure drops way low and I have to wait until my booster pump fills my pressure tank (86 gal.) again to build up pressure. I don't like this drop in pressure (down to a trickle) for a few minutes before the pressure tank fills enough to give me good pressure again.

I'm stumped because I installed an 86 gallon pressure tank so that I would have at least 20 gallons of full blast pressure before having to experience any kind of pressure drop. This happens especially when I don't use water for a day. I would think the pressure tank would hold 20 gallons for me when I need it. But I only get 1 or 2 gallons before I get this extreme pressure drop.

Here's my setup:
-Grundfos well pump (running on DC solar)
-puts water into 1200 gallon cistern
-Aquatec 550 12V DC booster pump pulls water out of cistern and into 86 gal. pressure tank.
-all my water lines (yard hydrant, utility sink, house main) are running from this tank.

I'm trying to finalize this setup so I can run my main water line to my house and finish my plumbing.

I'm about to just get a 115v AC pump and see if that works. Not sure what else to do! Any ideas would be greatly appreciated!!
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,439 admin
    #2
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    As I understand... There are two major types of pressure tanks... Simple Air over water and ones with some sort of air bladder inside.

    Air over water, there can be an internal float or external controller that will let compressed air into the tank when the air level/pressure get too low).

    And the tanks with an air bladder--You run the tank empty and set the air pressure for around 2 to 5 PSI below your pump turn on pressure (40 PSI switch on--35-38 PSI air pressure). This ensures you have "full pressure" down to near tank empty of water. And something like 1/2 the tank capacity of pressurized water (i.e., 40 to 80 PSI water pressure, tank empty to 1/2 full of water and 1/2 airspace).

    So--I would expect your tank to have around 40 Gallons of pressurized water--Assuming pump switch range is 2:1 (i.e, 80 to 40, 60 to 30 psi, etc.).

    If (when) the bladder fails, either the bladder or the whole tank will need to be replaced.

    https://cyclestopvalves.com/pages/pressure-tank-maintenance

    https://www.apswater.com/article.asp?id=308&title=Troubleshooting+A+Water+Pressure+Bladder+Tank
    https://dandkmotorsports.com/bladder-type-water-storage-pressure-tanks/
    https://inspectapedia.com/water/Water_Tank_Air_Volume_Controls.php (air over water/bladderless automatic controls)

    You could have two issues... One is a "water logged" tank (air bladder/pressure incorrect, leaking bladder)--And you could have an issue with the water pump itself (low GPM flow rate and/or low pressure because pump wet side needs rebuilding?).

    Do you know the pressure rating and GPM of the pump?

    https://www.solar-electric.com/lib/wind-sun/Aquatect_ds55xx-xx01-b636.pdf (12 volt pump)

    Something like 1-2 GPM for higher pressure pumps (i.e., 30 gallon of pressurized water storage / 1.5 gpm average flow = 20 minutes to refill tank).

    Anyway--My guesses.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • Miller_Ranch
    Miller_Ranch Registered Users Posts: 40 ✭✭
    #3
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    Do you have a check valve on the output of your booster pump?
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  • 706jim
    706jim Solar Expert Posts: 514 ✭✭✭✭
    #4
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    On the assumption that you have a bladder style tank it may have failed. They only last so many years before the bladder ruptures and the tank waterlogs. As you have pointed out, an 86 gallon tank should provide you with a lot of pressurized water before it goes flat. I had to change mine out after about 15 years.
    Island cottage solar system with 2500 watts of panels, 1kw facing southeast 1.3kw facing southwest 170watt ancient Arco's facing south. All panels in parallel for a 24 volt system. Trace DR1524 MSW inverter, Outback Flexmax 80 MPPT charge controller 8 Trojan L16's. Insignia 11.5 cubic foot electric fridge. My 30th year.
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  • Miller_Ranch
    Miller_Ranch Registered Users Posts: 40 ✭✭
    #5
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    Did this ever get figured out?
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