The Development of the Wood Pellet Boiler
Today's Designs are in or about the 1940 ies
I am beginning to arrive at the opinion that wood pellet boilers are where oil-fired-boilers were in 1940 to 1950.
Today you can purchase an oil fired boiler just about anywhere in the world and it will have all of the safety and efficiency features of most any other oil boiler. It will also have a price tag within a fairly tight set of brackets. Most burner units are standard and will fit into most boilers of a given output.
The unit does not have to be purchased as seperate bits, such as; oil pump, ignition unit, control box etc. etc. The burners, for the most part, are fully integrated units, with standard parts by companies like Danfoss etc.
Wood Pellet - Heath Robinson affairs
With Wood-Pellet-Boilers it is a different story altogether. Burner units are very varied in design. Bottom feed, top feed, lateral feed!! There are no standard safety features. All sorts of strange control systems unique to a particular manufacturer, and darn expensive for that very reason.
The fuel delivery systems are nothing short of "Heath Robinson" affairs. The systems, on a whole, are the equivalelt of DIY kits in a lot of cases.
Many of the boilers, in fact I would say most of the boilers, out there are modified lump wood burning boilers that have been modified to accept a pellet burner unit - stuck into the front or a side.
No Agreed Standards
There are no agreed standards yet. Such as a burn back prevention system, or a standard ignition system, a feed system, or even fitting flange systems. In a few years time many of the current clutch of wood-pellet-boilers will be seen as antiques and quaint objects suitable for museums.
A Twelfth Reason for not going Wood Pellet just yet.
Buying a wood pellet boiler now is simply subsidising the costs of development. In a few years there will be standardised units from Danfoss and similar, and the whole thing will cost a half or less of the current crazy prices.