First of all I have never used the water heater in my unit, last june I hooked up the hose to see if I had any leaks in the system and everything was good, so I opened the valves in the fw tank and the hot water heater, the fw tank did drain out but after 4 months there is still water draining from the heater, I want to put some RV antifreeze in the unit today but not sure what to do with the heater, I have angle the unit all the way down so the water can drain but it's still not empty, any suggestions?