I'm currently using a pump with a rated shut-off pressure of 69 PSI to supply a house with water. It is sucking through a 1.25" PVC pipe that extends 1100' into a lake. The lift from the water surface to the pump is about 15' and we are 1000' above sea level. Likely due to the lift and friction, the max discharge pressure I am able to get from the pump is 35 PSI.
If I change the pump to a larger jet pump with a rated shut-off pressure of 95 PSI, will I see a higher pressure at the discharge? Or will it simply flow more and the pressure will still be limited to ~35 PSI?
My goal is to supply the house with 40-60 PSI rather than the current 25-35 PSI. I prefer to do this with a single pump, but a booster pump in series is also an option.
Edit:
We have a 26 gallon diaphragm pressure tank after the pump. I'm seeing the peak pressure of 35 PSI once the tank is full. The pressure switch on the pump seems to be working but the pressure never builds higher (and the pump runs continuously unless the pressure switch is set lower).
It is possible our current pump has some worn components which is preventing the higher pressure being reached, even when the tank fills up and the flow is reduced.
Best Answer
With 15’ of lift you would loose about 7psi of pressure “static” I would be looking at your pressure switch, your system should be able to pressurize to ~62 psi with the long lines to the lake I would expect there to be large drops while water is being used but the tank pressure when full should be much higher, it is possible your “jet” is worn or your pressure switch needs adjusting I would look at these before just replacing the pump.
Added to address the edit. Since you can not get a higher pressure “static” now it is down to just a couple of possibilities, the jet is failing these are a fancy Venturi that creates the ability to push water it could be worn out (it happens) the pump may not be developing the needed pressure because of wear. I would want to verify the output pressure of the pump, if it is good then replace the jet (not that hard and less expensive than a pump. These are just about all that it can be (since you did not say anything about leaks).