Well you can't run it if the tank is low...that'll screw you. But one thing I found is my Hydronic will throw codes but if you don't touch the control panel it will restart on its own. Now with some codes a failed start can happen. I have driven for 15 minutes and seen an over heat code only to hear it fire up 30 minutes later as the vehicle sits. One of the problems I had at the beginning was after a code I would turned it off. Mistake, let it cycle. Now low fuel in another story.
For me the van sitting it isn't an issue. I simply fire it up before I leave out and go on my way. Pre heating the engine only helps. I do have solar so I'm not worried about low voltage.
Also you are talking about the water heater. This thread is about the cab heater...a different issue.
I did have issues with dirt and dust but I really think it was more user issues with me. After Greg repaired it (which might not have been needed) it has worked great. Just don't run it out of fuel.
Here was the post I made:
viewtopic.php?f=2&t=1729