If you choose to blow-out System...you may consider, after draining the water heater, re-open the heater by passes and blow thru to heater tank. There is a possibility (depending upon plumbing lay-out) that water could be trapped in low points. It takes only a few moments and assures that “no water is left behind”! ;) Leave your fresh tank drain valve open(it’s probably exposed), water collected against valve and freezing, could burst the line at the valve.
Without knowing your brand and design of you 5er, determining it’s “wintering capabilities” is near impossible. With electricity and propane, I’m good to a -30 F (and not lose any sleep) with water in the unit. Some units, because of tank/line locations and the units ability to provide heat to areas of water lines/tanks, are not safe for extended periods much below freezing. If you have forced-air heat to the basement area, running the heater in the unit (if you have electricity) should keep everything warm, “IF” the heat can get to “ALL” of the water utilities!
On the dishwasher, with your blow-out air (LOW PRESSURE) on the system...run the dishwasher through a cleaning cycle (same with washing machine, if equipped). This should void the system (piping but not the pump) of water. As an extra precaution on the dishwasher and the washing machine... pour some RV antifreeze into unit ( to get antifreeze into the pump) and then run the pump. With the ice maker, the same. With system pressurized with air.... it should blow thru as though it were trying to make ice cubes.
I know that this may sound like overkill, but I’m from Baton Rouge area....and in the 35 years I lived there, I saw single digit temperatures twice. Though not predicted to get that cold, all it takes is once... if your not thourghly “winterized”!
