Answers to some of your questions can be found in the Vedolux boiler manuals which you can download here:It looks easy enough. I just want to make sure my wife can handle lighting without an issue. My next question is to size the unit I need. I currently use propane 170KBTU max, 7 zones hydronic/forced hot air. My house is 5500 sq/ft heated, and my external garage is 1250 sq/ft (625 sq/ft per floor). The garage is unfinished but I would like to heat it in the future. How can I estimate the unit size (BTU output) for my current needs? I also have questions on the unit operation. If I fire up the unit but my storage is at temperature does the unit shutdown/smolder until the water temp drops?
Here is the section of the manual describing the over-temperature protection features of the Vedolux boilers.
It might be helpful to calculate the expected temperature rise for each Vedolux model for various storage tank volumes. We start with the number of BTUs in a cubic foot of wood. In my case I burn a 50/50 mix of Ponderosa Pine and Douglas Fir.
one cubic foot = 120,000 BTUs assuming moisture content less than 16%.
Then we can calculate the expected temperature rise. We will assume that the firebox volume can really only be filled to about 80% capacity with wood and a boiler efficiency of 74%.
These temperature rise numbers are added to the starting temperature of the storage tank to establish the expected final temperature when a burn has been completed. For example, if the tank temperature at the start of a burn is 120°F and the expected temperature rise of a Vedolux 650 is 75° in 800 gallons, the final tank temperature may reach 195°. This will exceed the 194° maximum temperature limit of the boiler control and will trigger the boiler protection described above.