Booster Pump in-line with Submersible

[ady]

I have a new submersible pump installed in a newly bored well for a new house. However I am considering installing a variable speed booster pump like;

Lowara 2HM5 Water cooled Hydrovar pump and controller
With an 8 liter pressure kit
11/4 inlet feed with a 11/4 non-return valve
1 inch lever valve on outlet.
2.2 bar on a constant pressure.
Deliver 60 liters per minute at this pressure.

in-line after the buffer tank for the submersible pump before I get all my plumbing connections completed.

My question is will this cause problems? Is it likely that the booster pump could run dry because it is calling for water faster than the submersible can supply or will this depend on some mathemathics in calculating the time it would take for the buffer tank to run dry if the booster pump is running at full speed?

If so would the following avoid this problem;
Put a float switch in the buffer tank which shuts down the booster pump for a given period of time to allow it to refill. I realise this sort of defeats the purpose of the pump in the first place but I was thinking I could try this and monitor it to see if it is actually required. If it is required then I could look at increasing the size of the buffer tank. As I am an electrician the controls I am talking about would be cheap and relativly simple where as increasing the size of the buffer tank is a problem with regards to space.

[valveman]

If the well is a low producer, then a storage tank, booster pump, and pressure tank will be needed. If the well is a good producer, then you need to accomplish everything with the well pump, and a booster pump is not needed.

If the storage tank is needed, then a regular jet pump, pressure tank, and pressure switch would be more dependable and less expensive.

However, if you like selling things that cost a lot and don't last very long, then a variable speed pump is what you need.

[mickeygil1]

How??? I have a new well 500' away from my house and I want more pressure at the house. I currently get about 40 psi at the house, I have a 3/4 hp submersible pump 40' in a 8" hole coming up to an 20 gal. pressure tank with a 40-60 pressure switch. How can I increase the pressure with out installing a pressure booster.

[valveman]

With the pressure switch you have, you can probably turn it up to about 55/75 before the spring collapses. (Use 50 PSI air in the tank) That maybe all you have to do to get the pressure you want.

Assuming you have about a 10 GPM, 3/4 HP pump, it will make up to about 100 PSI safely. You can get a GHG type pressure switch and turn it up to as high as 80/100 if need be. (Use 75 PSI air in the tank)

The higher the pressure, the less water is in the 20 gallon tank. At 40/60 it holds 5 gallons, at 80/100 it only holds 3.5. So you have to make sure your pump does not cycle excessively. May need to add another tank or a CSV.

The size of the 500' line is what makes most of the difference. If that line is large enough, you will have the same pressure at the house that you have at the well. If that line is too small, you will only have good pressure at the house in one little spurt as the flow increases and the friction loss adds up. If the line is too small, a booster pump can't suck more water through it either. You would need a storage tank and then booster pump with pressure tank to be able to have more flow than the small line would accomodate.