Newbie question on Espar Hydronic

[lynx1]

Hey All,

Glad to find this forum and hoping there is some expert advice/opinion for a newbie forum member and a not quite as new SMB owner (last January). Here's my question:

The van has the Espar Hydronic D5WS furnace and hot water heater. If I am going to winterize the water system (no water) can I still use the furnace? It kind of doesn't make sense to me that they would make a system that I would have to run a heater constantly to keep the water from freezing if I am only using it intermittently. But I don't want to burn it up finding out.

Thanks for the help.