I have just installed a new submersible pump and a retention tank. The hose between the pump and the tank has to be emptied automatically to prevent the system from freezing during winter. So every time the pump kicks on, the air in the hose will be pumped in the tank. The plumber suggests a 40 gallon rentention tank with no membrane but with a vacuum breaker installed at the half high of the tank to evacuate the excess of air. Once installed, the system works perfectly. The pressure switch is set to 30-50 psi. However, every time the toilet is flushed, the pump kicks on. In another word, only 3 to 4 gallons of water drawn will activated the pump. This is too little compared to a tank with a capacity of 40 gallons.
Is there any way the situation can be improved or should I use another type of tank, such as a bladder tank or change a 25-50 psi switch ?
Thanks.
Snowsun

I'm no pump guy and I just proved it in another thread but wouldn't bleeding the air out of the pressure tank take away the air cushion and force the pump to kick on every time s draw was made? Why not treat this like a regular pressure tank with no vacuum breaker and a valve on top to relieve the air lock when you drain it for the wenter. Why evacuate any air at all when you turn the system back on. That air will compress and send pressure out without the pump running each time you flush or make a draw. If I've missed something here please let me know. Regards, Tom