OK I see I'm not connecting here.. If the water pump is left energised, if he has a heat failure and pipes break the pump could pump water in his house untill some one turns it off. If the pump is turned off and potable water side is drained, the only damage would be a few gallons of water on the floor somewhere instead of thousands of gallons. I didnt say turn the heat off. I said turn the well pump off. The plumber told him it couldnt be done because the boiler requires water from the well for makeup water in the boiler system. The single pressure tank charge would supply sufficient water for make up for the boiler to operate for a year unless he had a bad hydronic leak. The well pump should be turned off, the potoble water side drained and the boiler left operational on winter mode. Surely I can't be the only one seeing this.