Closing my camp and want to pump RV anti freeze into the tankless coil and all the domestic lines in the hot water boiler. The house has a well trol, do I pump down the cold side from the well trol drain. By doing this will this drain the hot side from the well trol drain? Then remove the pressure relief valve and screw on a gate valve and pump anti freeze into the domestic side. Then after pumping a while open all the faucets. Can anybody comment or have recommendations.