The highly-efficient Timberline hot water and heating system is included in the Interstate 24X, the Rangeline Touring Coach, and any motorized Airstream with the optional E1 Package.
Winterizing the Timberline system is easy and involves just a few simple steps. No winterization is required of the system coolant, but the domestic water circuit must be drained or protected using RV non-toxic antifreeze.
Draining the domestic water system is accomplished by opening the low point drains and blowing air through the water system (check your manual for low point drain locations).
Non-toxic RV antifreeze can be pumped through the system using the domestic water pump and opening both hot and cold valves at a plumbing fixture. Using this procedure does not require draining the Demand Hot Water exchanger.
You can learn more about preparing your touring coach for winter storage here.