Here’s my situation – new house and well. The well is 300ft deep and the water is at 60 ft below the ground level, so I have about 360 gallons of storage in the well. The yield is only 1gpm. Two and half baths, washer, washing machine, etc. Also I am off the grid, running on a generator and batteries. My electrician suggested I should get a pump that is soft-start and no more powerful than 3/4 HP.
Based on this and after talking to my plumber I got the Grundfos 5SQ07-320 pump, and a wx-250 tank. The pump will be installed at 280 ft, i.e. 20 ft above the bottom of the well.
Assuming 30-50 pump cut-in/cut-out, and looking at the Grundfos performance chart at 30 psi, the flow will be between 8 gpm and 4.4 gpm depending on the water level in the well. How realistic are those numbers? Do I have to adjust for friction loss, etc. considering the pump will be almost 300 ft down?
Also, let’s say the demand exceeds the pump output for a long period of time. What happens to the flow after the pressure drops below 30 psi ? Does the flow get interrupted because the air is completely expanded in the tank at, say, 28 psi or is there a bypass valve of some sort to allow the water to bypass the tank? In the latter case I would imagine the pressure will continue to drop until the pump can keep up with the demand (maybe, say at 20 psi).
The wx-250 tank has a draw down of about 15 gallons at 30-50 cut-in/cut-out. Is there a way to make sure that first thing in the morning before anyone has taken a shower the pressure is at 50 psi? I would like to avoid the situation where the pressure was left at, say, 31 psi from the night before, and there is little to no reserve of water in the tank.
Finally, what do you think of the Cycle Stop Valve? On the one hand I like the constant pressure, on the other I understand you lose 1/2 gpm of the flow, which is significant in my situation. I am not too concerned about the number of cycles, as the tank is sized appropriately relative to the output of the pump. Also, I am not too concerned about the startup spikes in electricity, as the pump is soft-start. I would like to have a more constant pressure in the system, though.
Thanks for your help and advice!
Based on this and after talking to my plumber I got the Grundfos 5SQ07-320 pump, and a wx-250 tank. The pump will be installed at 280 ft, i.e. 20 ft above the bottom of the well.
Assuming 30-50 pump cut-in/cut-out, and looking at the Grundfos performance chart at 30 psi, the flow will be between 8 gpm and 4.4 gpm depending on the water level in the well. How realistic are those numbers? Do I have to adjust for friction loss, etc. considering the pump will be almost 300 ft down?
Also, let’s say the demand exceeds the pump output for a long period of time. What happens to the flow after the pressure drops below 30 psi ? Does the flow get interrupted because the air is completely expanded in the tank at, say, 28 psi or is there a bypass valve of some sort to allow the water to bypass the tank? In the latter case I would imagine the pressure will continue to drop until the pump can keep up with the demand (maybe, say at 20 psi).
The wx-250 tank has a draw down of about 15 gallons at 30-50 cut-in/cut-out. Is there a way to make sure that first thing in the morning before anyone has taken a shower the pressure is at 50 psi? I would like to avoid the situation where the pressure was left at, say, 31 psi from the night before, and there is little to no reserve of water in the tank.
Finally, what do you think of the Cycle Stop Valve? On the one hand I like the constant pressure, on the other I understand you lose 1/2 gpm of the flow, which is significant in my situation. I am not too concerned about the number of cycles, as the tank is sized appropriately relative to the output of the pump. Also, I am not too concerned about the startup spikes in electricity, as the pump is soft-start. I would like to have a more constant pressure in the system, though.
Thanks for your help and advice!
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