[beeje]

My method in not very popular here but it works well and can be done in 10 minutes if you have a unit with a gravity fill port. I tilt the unit with the level up so that the drivers side is way low. Turn the water heater to bypass. Dump in 3 gallons of antifreeze into the fresh water tank. Turn on the pump and pump it through all fixtures until you see pink. Then turn the bypass off so a little goes to the water heater with the drain open and running pink. DONE.

It the spring, just run several tanks of fresh water through the system to flush out the antifreeze. There may be a little residue left ( that will clear up quickly with use) , but most of don't drink the tank water anyway.