Dual water tanks and Well pumps

[Pmcltd]

Here is a new challenge:

Two wells/pumps:

• Well #1 (Primary) 10 GPM – 1 HP
• Well #2 (Secondary) 5 GPM – ½ HP

Each well pump has its own starter, pump saver and local disconnect.

Both wells have new pumps.

A pump house that encloses:

• Two 5000 Gal water storage tanks
• Tank 1 is a primary Tank – dual purpose – domestic water and fire sprinkler water
• Tank 2 is a static storage tank for fire water
• Tank 2 is connected (3”), at the bottom, to a 6” yard fire standpipe with connection for a fire department pumper truck
• Tank 1 is connected at the bottom to the 6” line to the yard fire standpipe with a 3” pipe and double backcheck
• Tanks 1 and 2 are connected together with a 2” pipe that feeds the fire water pump. Tank 1 is connected downstream of the 3” double back-check valve.
• A 45 KW emergency generator
• A 2” fire water pump feeding the fire sprinkler system in the house/shop
• A 1-1/4” variable speed pump that feeds domestic water to the house/shop, summer kitchen and for irrigation. The draw point for the domestic water variable speed pump is at about mid height on Tank #1

Each well pumps into the pump house through its own 1-1/4” pipe to a spin-down filter on each line into a header that then feeds into the 5000 Gal storage tanks. Tanks operate in parallel, not series.

Once the domestic water reaches the house it goes thru a pair of “Big Blue” filters, a UV Filter and a water softener.

Here are my thoughts:

Each tank is filled from the header pipe through a 1-1/4” motorized ball valve, one for each tank

Water level in each tank is controlled by float valves

Thinking may need a second float valve in tank 1 to lock-out the VS domestic water pump to prevent sucking a dry head in the event of a fire event that could draw the water level in Tank 1 below the draw point for the VS domestic water pump especially if a pumper truck is connected to the yard stand-pipe drafting from both tanks at the same time. The theory is that if everything fails (utility power and back-up generator), the pumper truck can connect to a 3” fire water connection at the house/shop and pressurize the fire sprinkler system.

Don’t want both well pumps coming on at the same time

Trying to figure out contactors/relays that control the well pumps, float valves, motorized ball valves etc.

 

[Valveman]

Use a 24V solenoid with flow control instead of motorized ball valves. Adjust the flow control knob to use 15 GPM, to use max flow from both pumps. A regular pressure tank and 40/60 pressure switch is all you need to control both well pumps. Just make sure to fill the tanks at 15+ GPM to keep the well pumps from cycling on and off, and let both pumps run at the same time.

Both storage tanks need so be connected and water drawn from the last tank, to keep the water fresh in both tanks. A float switch in the last tank would open the solenoid valve, allowing the pressure to drop so both well pumps come on. A second float switch in the pump down configuration set high in the storage tank can prevent the booster pump from running when the storage tanks drop to a certain level. I doubt there is any way to connect this float switch to the variable speed type booster pump. So, you will need a relay prior to the booster pump which uses the float switch to disconnect power to the booster pump.

You could have used a normal jet pump with a PK1A to control it. The CSV in the PK1A would give strong constant pressure to the house and make the pump system much more reliable and longer lasting than the variable speed booster. With a normal pump like this the pump down float switch would just be connected to the pressure switch on the booster pump, and an additional relay would not be needed.

 

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[Pmcltd]

Cary,

Thank you for the reply. I am going to digest, draw myself a couple of sketches of what you are suggesting and get back to you. To make sure I understand, the jet pump and PK1A that you suggest would have been an alternate approach to the VS speed pump - had I not already bought the VS pump. If so, that ship has already sailed.

I also already have the 3" double backcheck valve. One 5K gal tank would be more than sufficient to supply domestic and irrigation water. The second 5K gal tank is only needed to have 10K gal available for fire protection. Southern, rural Oregon in a high wild fire risk area. That is why I have intended to leave the second tank as an separate/static tank and only have to filter/treat water filling one tank. The separate/static tank would only draw water from the header feeding both tanks in the event of a fire event.

I will attach my sketch to a subsequent post, if that is OK?

 

[Valveman]

No problem as the VS pump won't last long, which is why we replace so many of them with a Cycle Stop Valve. You need to draw water through both tanks. If not the water in the "static tank" will get green and slimy in a short time. Pulling water through both tanks everyday keeps the water fresh.

Here is a drawing that might help. Both well pumps can be teed together before the solenoid valve.