The PN-EN 303-5:2012 standard came into force in 2014 and introduced 3 boiler quality classes, at the same time withdrawing the previous classes 1 and 2. The criteria of the standard concern gases emitted during the combustion of solid fuels, especially tar, dusts and carbon oxides. The standard regulates the minimum nominal power at the level of 30%. 5th class boilers are products of the highest quality. Their minimum efficiency is 88%. They emit over 90% less pollution than old furnaces! Let’s see what is worth knowing about them.
Manufacturers of 5th class boilers convince us that this solution is beneficial not only for the environment, but also for our wallet. 5th class boilers emit less than 10% of pollution, operate in an undetectable way, have a positive impact on the cleanliness of combustion, consume less fuel and increase the efficiency of heating processes. They are ecological and easy to use. Since 2017 in Poland, each boiler manufacturer has been obliged to manufacture only appliances that meet the requirements of 5th class. These are nowadays the cleanest furnaces for burning solid fuels. They burn a small amount of fuel at once, producing minimal amounts of soot and tar. For this reason, it is possible to reduce emissions of harmful fuels by almost 90% and thus contribute to the reduction of the smog effect. This is very important in the era of special care for the quality of the air we breathe.
The Ecodesign Directive enters into force in 2020 and provides for the compulsory replacement of non-class boilers with 5th class boilers within 5-10 years. In addition, it sets thresholds for nitrogen oxide emissions, introduces energy labels for boilers and a requirement for manufacturers to provide information on the average seasonal efficiency of the boiler. The aim of the Directive is to improve energy efficiency while respecting the natural environment.
5th class boilers are usually equipped with an automatic feeder and are designed for combustion of pellets from non-wood biomass and coal. The lack of an emergency grate makes it impossible to burn other types of fuel. The temperature of exhaust fumes in 5th class boilers should not exceed 110 degrees Celsius. At lower rated output and lower temperature, the boiler will be exposed to corrosion. This can be avoided by using thermally insulated chimneys with corrosion protection in the form of ceramic or acid resistant inserts. Otherwise, damp flue gases will penetrate into the building. The flue pipe must be resistant to acidic condensate. Lack of thermal insulation means that the temperature of the flue gases drops. It is possible to increase the efficiency and service life of the boiler by using dry fuel. Moist fuel should be dried on its own. The fuel should not contain more than 20% water. Do not use fuels with high sulphur content. 5th class boilers require regular cleaning of internal heating surfaces. It is important that no soot or volatile dust is deposited inside the boiler. It is also necessary to keep an eye on whether the vacuum generated by the chimney is sufficient to resist the flue gas flow.