BS EN 304:2017 pdf download.Heating boilers – Test code for heating boilers for atomizing oil burners.
6 Measurements for the heating mode 6.1 General The amount of useful heat output transmitted to the heat carrier (water) is measured. It can be determined in the boiler circuit or by means of a secondary heat exchanger. The useful heat output transmitted to the water is determined either by measuring a) the mass flow of cold water entering the boiler circuit and the rise of temperature between the outlet water temperature and the inlet water temperature; or b) the mass flow of the water circulating in the boiler circuit and its temperature rise; or c) the mass flow and the temperature rise over a secondary heat exchanger corrected by the heat loss of this secondary heat exchanger. The heat produced by the boiler is transferred to the cooling water by means of a secondary heat exchanger. The heat received by the latter is calculated from the mass flow and the temperature rise of the cooling water. The heat losses from the well- insulated connections between the boiler and the secondary heat exchanger and those of the secondary heat exchanger itself, are determined either by preliminary tests or by calculation. The heat output of the boiler is the sum of the two amounts of heat.
6.2 Determination of the nominal heat output The tests for the determination of the nominal heat output shall be carried out at a firing rate such that the output is at least 100 %, but does not exceed 105 % of the nominal value, and the requirements concerning the nominal heat output shall be met. If the heat output exceeds 105 %, a second test shall be carried out at a firing rate between 95 % and 100 % of the nominal heat output of the boiler. The actual value for the nominal heat output shall be determined by linear interpolation between the two test results. The nominal heat output shall be determined at a water rate that is adjusted to obtain a return water temperature of (60 ± 1) °C and a temperature difference between the flow and return water temperature of (20 ± 2) °C. NOTE The conditions for determination of the rated heat output in former versions of EN 304 have been a mean flow temperature of between 80 °C and 90 °C, and the mean temperature difference between flow and return has been between 10 K and 25 K. However, this is not in line with the Regulation EU 813/2013.
6.4 Performance of testing 6.4.1 General test conditions The boiler is installed in accordance with the technical instructions in a well-ventilated, draught free room (air speed less than 0,5 m/s), which has an ambient temperature of (20 ± 5) K. The boiler is protected from direct solar radiation. The settings of the burner shall not be manually changed after adjustment. No change shall be made to the water flow or any other test parameter during one test period. The temperature, pressure and composition of the products of combustion shall be measured continuously and shall be recorded with a sampling rate below 10 s. The flow temperature t F and the return temperature t R shall not differ by more than 0,5 K/h × test period [h] at the beginning and the end of the test period.BS EN 304 pdf download.