Re: Winterizing Questions for Garaged Sportsmobile
To the core of your question then, water expands in all directions when it freezes. If residual water has filled a tight space it can stretch or break the container holding it. Pump chambers are good examples of this, but there may be small valve chambers at risk too (e.g., city entry valve with backflow and over-pressure restricter). Even a pipe trap, such as the one attached to the sink, can crack due to width-wise freeze expansion. Jage blows down his water system which is one way you can minimize the risk of residual water freezing. Something else to keep in mind is that a pipe may not break, but become fatigued over the years of being stressed by freezing water pressure and I doubt it's very good on the gaskets and joints either.
2010 Ford E250 5.4L V8 Gas 2WD
SMB Mod RB36 w/PH Prop Stove & Furn Frig 10G Wtr Elect