I changed the catridges on my system. Now the tank fills for about 45 minutes with all the valves except the drain line open. It empties in about 10 minutes. Water is not continuously running to the drain. The pressure of the tank is 7.5 psi. It seems the system shuts off when it is partially full as it does not make a sound. Then I close the mains line and open the faucet and it's all gone in 10 minute.
Any help appreciated?