Last outing on the boat I had problems with the Wallas stove/heater shutting down several times.

What always preceded the shutdown routine was the unit producing lots of white smoke out the exhaust. Called Scan Marine down in Seattle and spoke with Karl. After explaining to him what happened, he asked me about my fuel. I told him I use K1 kerosene and had been doing so for the past couple of seasons. He asked if I emptied out the fuel every fall when winterizing. I said no, I was not aware of that requirement. He said I should every year dump the old fuel out, clean the filter and tank, and then refill with fresh kerosene.
After doing some research on storage of kerosene, I was surprised to learn that kerosene only stores for 3 or 4 months before starting to degrade. :shock: When I pulled my tank out and empty it into several containers, low and behold, I had about a cup of water in the bottom of the tank and some dark sludge looking stuff. Wow, no wonder I had problems with my Wallas stove/heater!
I also discovered the source of the large amount of water in my tank. The vent tube for the tank was simply dropped in the bilge by the installers. My tank is the 10-liter model and is strapped down next to the bilge in the cabinet. When the stove/heater sucked fuel out of the tank, the vent tube had been sucking water out of the bilge!!! :cry So, I redid the vent tube by running it up the inside of the cabinet so the top was about an inch below the countertop, securing it with those black plastic cable clamps.
Tested the unit last night and it is working fine now with fresh kerosene.

:thup I did add about 4% isopropyl alcohol to the kerosene to bind any condensed water in the tank.
Lessons learned: 1) Make sure your fuel tank vent tube is not sitting in water. 2) Empty out the tank every year, clean it and the filter. 3) Use fresh kerosene at the beginning of every season.
Sure would be nice if the owner’s manual that came with the Wallas said something about kerosene not lasting over a winter and the tank and filter needing cleaning once a year. :disgust Oh well, you live and learn.
Hope this helps someone out with their Wallas stove/heater before they have trouble.
Jim