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Condensing Wood Pellet Boilers

Grant biomass boiler rangeWood pellet boilers are an environmentally friendly, safe and convenient way of heating the home, using wood pellets as fuel.

Apart from the green aspect, the units are fully automatic and behave more like an oil or gas boiler, using advanced controls which cleverly regulate the amount of fuel being delivered to the burner to match the heat demand on the boiler. The fuel is fed to the burner via an auger connected to the adjacent pellet store/hopper. This can, in turn, be automatically supplied from a bulk pellet store which can vary in size.

The process of burning wood produces ash, so wood pellet boilers, biomass boilers  normally require a certain amount of regular cleaning and maintenance, which can be tedious. Grant has, however, has a better solution with a unique ‘self cleaning’ boiler design, reducing the need for cleaning to once a year under normal running conditions.

How a Grant wood pellet boiler works

On start up the auger feeds the wood pellets from the hopper into the burner where it is lit by an ignition element. The burner output modulates to achieve the set temperature by controlling the feed rate of pellets. The fan in the burner propels hot gas generated from the fuel into the Spira’s primary heat exchanger. The heat energy is then transferred to water from the central heating system, before being circulated around house to radiators/underfloor. It is important to note that in modern pellet boilers, up to 20% of the energy that is produced is lost to the atmosphere through waste gases exhausted by the flue system, The Spira has a unique secondary condensing heat exchanger which has been designed to capture some of this lost latent heat energy, so it can maintain extremely high efficiencies. The boiler’s fully automatic cleaning system will periodically wash the condensing unit of any debris in the tubes and also activate the brazier within the burner to clear the combustion chamber of ash build up, which reduces maintenance time.

Unique and efficient boilers

The MCS approved Grant Spira condensing wood pellet boiler utilises the award winning patented stainless steel Vortex turbulator baffle system and has many benefits including:

  • A rapid ignition system with modulating burner. This means our boilers operate in much the same manner as a standard gas boiler to give you a greater degree of control of your energy output and control.
  • Require little intervention. Grant are proud to have a unique self-cleaning design and automated fuel feed so the need for you to intervene is kept to a minimum.
  • Lower energy consumption and greater efficiency than our competitors. A boiler using biomass fuel is far more cost effective to run than fossil fuel boilers.  Due to the extreme efficiency of our boilers (up to 97%) thanks to our award winning patented baffle system, we are able to provide you with the most efficient boilers on the market.
  • Suitable for home use. Grant wood pellet boilers are a safe and convenient way to heat your home.  One thing to consider is the amount of space you may require for the boiler and pellet hopper/store.  The boilers use an automatic feed for the wood pellet fuel too which means more convenience for you.

Grant Biomass Forum

The Grant Biomass Forum is a new hub designed to help our customers find product related technical information and have discussions with other forum users about the Grant wood pellet boiler range and accessories. There are areas for G-One installers, training courses and industry legislation too. Access the forum here:


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