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Why you should service your biomass boiler

Posted by Gabriel Wondrausch on 29 June 2012 at 9:40 am

A biomass boiler is classed as a solid fuel appliance and as such produces a waste product, apart from flue emissions, this waste is ash. Ash production is around 3% for wood chips at 30% moisture content and much lower for pellets at around 1%.

Ash is a highly insulative material and due to the nature of the passage of exhaust gases through the boiler and the combustion process, coats steel surfaces in contact with it very easily. If ash is coating a particular area of the heat transfer section in a biomass boiler, then heat dissipation is greatly reduced. If the heat transferred has been reduced then more fuel is required to be burnt to get the same amount of energy from the boiler.

In order to maintain the thermal efficiency of a boiler, it is important that it is cleaned regularly. A good indicator of a biomass boiler slowly reducing in efficiencies is an increase in flue gas temperature as the heat produced is being wasted through the flue.

Most boiler manufacturers provide at least some basic information on boiler servicing in their operators manuals. It is also important for a manufacturers recommended service engineer to regularly carry out a more thorough service on the boiler. He will not only clean it and maintain boiler efficiency, but will also have the skills and knowledge to spot other parts that are deteriorating or require replacement.

Biomass boilers also contain a lot of mechanical moving components, for example, in fuel extraction systems, de-ashing, systems and combustion air fan actuators. These need to be lubricated regularly to ensure their smooth running and again, to maintain boiler efficiency.

Most of the more involved servicing of a biomass boiler is generally out of the end users ability as they will not be trained or skilled to the recommended level by the boiler manufacturer, thus the need arises for a skilled engineer to pay a visit once or twice per year just to keep an eye on things.

It is more cost effective to arrange for a regular service visit than to continuously call an engineer out to repair a failed boiler because it hasn’t been serviced properly. Not only that, but it is better for your pocket as fuel consumption is greatly reduced. As with all solid fuel appliances, flues and chimneys must be swept at least once per year too.

Modern biomass boilers are becoming more user friendly and the regular intervention required is not as much of a task as it used to be. I think boiler manufacturers have taken this on board to make their boilers easy to look after with a minimal amount of work required and still managing to maintain efficiency levels at around 90-93%. There’s not many aged oil or gas boilers that can boast that. As with all things of a mechanical nature, take care of it and it will serve you well!

Written by Mike Castle, Biomass Eng. since 2002, photos SunGift Solar

About the author: Gabriel Wondrausch is founder and director of SunGift Solar, which installs solar thermal and other renewable energy systems in the South West of England.

If you have a question about anything in the above blog, please ask it in the comments section below.

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1 comments - read them below or add one


derrickmarcelComment left on: 18 March 2014 at 5:41 am

Also need to service your boiler regularly to make sure there is no dangerous build-up of carbon monoxide gas in your home.

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