I am in the process of winterizing my new raypak heater. There seems to be nothing in the manual about removing the pressure switch or emptying the water out of the plastic bowl of the anode. Since the pressure switch opening is facing down I would assume all the water would drain from it when I remove the drain plug and pressurize the system with air. The plastic on the bowl that is still filled with water, seems to be thick enough resist breaking during the winter freeze. Any advice?