How can I winterize a set of Polaris heating units?
Draining the units is a good idea. Before you do that, you should pump RV Plumbing antifreeze into the system. That way any water remaining in the pipes will not freeze. Also do the toilet bowls and anything else that you think could hold water. The trick is to get it everywhere in the system. It's not always easy if you are not familiar with the principles of plumbing. There are heat exchangers and pumps in those Polaris units. Very expensive to replace due to freezing and cracking. Only do it if you are very confident that you can get the antifreeze everywhere. Don't simply drain the system as you may not get all the water out and risk destroying your units. Another option is WIFI thermostats that notify you if the heat shuts down. Very expensive for 11 cabins but a great solution for long term monitoring.