A comment
The Viadrus boiler, model U22 D, was installed a little over 3 years ago. We drown with firewood, though this winter I got wet firewood, at first I was worried, but then it turned out that he eats such without problems. There is an accumulative capacity (a huge plus for all boilers), first it accumulates heat, and then it starts to spend.
There was one incident with the boiler, I decided to try to save on firewood and began to close the valve. A week later, soot began to burn in the pipe and, accordingly, the boiler within 30 minutes, without ceasing for 30 minutes.
There is a draft regulator, it works in automatic mode. When it is necessary, the boiler starts to dampen itself, when the water temperature starts to cool, it flares up. Once it overheated it to 120 C, the boiler withstood everything with dignity.
Very heavy in weight, at least 4 men will be required for installation.
pros
easy to operate, reliable boiler
Minuses
eats only short firewood up to 34 cm