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As a general rule the simpler less expensive units require more supervision and intervention by the owner while more sophisticated units take care of more functions automatically.
It is vitally important that you ensure the stove or boiler is properly matched to the application.
Wood Pellet stoves
Pellet stoves are designed to produce hot air for space heating. They are consequently relatively small in size, up to about 10 kW in output. The pellet fuel is loaded by hand into the integral store every few days according to heat demand. The fuel is delivered to the burning grate by gravity and augers. Spent fuel falls from the burning area into the ash pan at the bottom of the stove.
Cleaning of the fire grate and removal of ash is done manually.
Some stoves are equipped with thermostats, timers and automatic ignition systems and the facility to reduce heat output to about one third of the maximum available to make the stove more versatile in operation.Wood Pellet stoves with back boilers
These units are very similar to the pellet stoves with the addition of a back boiler which allows heat to be distributed through a new or existing water filled radiator central heating system. The more advanced models have all of the control facilities already described. Cleaning of the heat exchanger plates is carried out by means of rods which are operated to remove any particle accumulation which would decrease the efficiency of the heating process.
Boiler sizes are typically 15 to 22 kW with about 7 kW available for space heating and the balance powering the central heating system for example this could be suitable for a three-four bedroomed detached house.
Pellet boilers
This equipment performs in a similar way to wood chip boilers which are described on page...
Pellet boilers can work in tandem with heat accumulators. The main difference in operation is the fuel storage which can be in a conventional silo such as is used for animal feed and the transfer of the fuel can be by means of an auger or a pneumatic system which moves the fuel to the boiler infeed. It is essential that pellets are kept completely dry as they are rendered useless if they absorb any moisture.
Currently the higher cost of the fuel means that these units will be used primarily where on site space is restricted.
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