ncgeo
In the Trades
I have an 86 gal bladder tank on my well eqipped with a 3/4 HP 12 GPM Meyers Predator pump, set at about 32/52 psi cut-in/cut out pressure. The well is used to operate my geothermal heat pumps only with maximum flow of 9 GPM. The drawdown on the tank is about 25 gal at those pressures, and with the heat pumps running the runs for about 3 minutes and is off for about 2-1/2 minutes. Since on the coldest nights the heat pumps run near-continuously that still seems like a a lot of cycling, so I am considering a CSV.
If I set the CSV pressure to about 40 psi I understand that during use the tank pressure will go down to the 32 psi cut-in at which time the pump will kick-in. It will supply the 9 GPM for the heat pumps plus additional to fill the bladder tank until it reaches the 40 psi CSV set pressure. At that point the tank and CSV will be at 40 psi, and the CSV will only flow the 9 GPM while the heat pumps continue to run. When the heat pumps shut down, the CSV will reduce pump flow to 1 GPM until the tank fills reaches cut-out pressure. I figure this could be as long as 15 minutes(!) based on tank capacity.
Does all of this sound correct? I am most concerned with the interval after the heat pumps shut down and the CSV is generating minimal flow. During that time everything between pump and CSV will see high head pressure, and with just 1 GPM flow the pump may overheat. Is it better to use a CSV with a small tank for this reason? I'd prefer not having to replace the tank.
If I set the CSV pressure to about 40 psi I understand that during use the tank pressure will go down to the 32 psi cut-in at which time the pump will kick-in. It will supply the 9 GPM for the heat pumps plus additional to fill the bladder tank until it reaches the 40 psi CSV set pressure. At that point the tank and CSV will be at 40 psi, and the CSV will only flow the 9 GPM while the heat pumps continue to run. When the heat pumps shut down, the CSV will reduce pump flow to 1 GPM until the tank fills reaches cut-out pressure. I figure this could be as long as 15 minutes(!) based on tank capacity.
Does all of this sound correct? I am most concerned with the interval after the heat pumps shut down and the CSV is generating minimal flow. During that time everything between pump and CSV will see high head pressure, and with just 1 GPM flow the pump may overheat. Is it better to use a CSV with a small tank for this reason? I'd prefer not having to replace the tank.