Ok. Thanks for the input. I DID flush and drain the entire system prior to adding the antifreeze. The hot water heater drain was opened and everything gurgled out. There is no simple way to add a siphon, which is irrelevant since a HW bypass cant be easily added due to crowding from an aftermarket supplemental electric addition w/a wall switch to the gas HW heater.
I added 12 gallons of antifreeze to the purged system, made sure it ran heavy pink through all faucets, dumped some extra in the holding tanks, then opened all faucets and hot water heater drain and low point drains and let it run out.
Im satisfied that there is no water anyehere in the system and dont see any need to leave liquids in the plumbing for the winter, which tends to be severe with feet of snow at times. I am satisfied that any residue is antifreeze only.
I did not think to recycle the antifreeze as was suggested by another prowler owner. I will definitely do that next year.
As I said in my original post, I have always had someone blow out my water lines with an air compressor. Last year, he used too much air pressure by accident and caused a leak. Of course I did not realize this until the following spring and I am very lucky that the leak was obvious and easy to access and fix under the kitchen sink.
When I figure out how to post pictures, I will post some of Big Bertha. It is always a conversation starter whenever I pull into a Campground. She is very clean inside and out. She even has a 1968 Schwinn Twinn tandem bicycle on the back.
