BS EN 304-2017 pdf free download.Heating boilers – Test code for heating boilers for atomizing oil burners
The full range of the measuring apparatus shall be chosen in such a way that it is suitable for anticipated value. The measurement accuracies indicated above concern indivi dua l measurements. For measurements requiring a combination of individual measurements , the lower accuracies associated with i ndividual measurements may be necessary to attain the total requi r ed uncertainty. T he test rig sha ll be set up in such a way that the efficiency can be determined within a uncertainty of 2 % pomts .
6 Measurements for the heating mode
6.1 General The amount of useful heat output t ran smitted to the heat carrier (wa t er) is measured. It can be determined in the boiler circuit or by means of a exchanger. The usefu l heat output transmitted to the water is determined either by measuring
a) the mass tlow of cold water entering the boiler circuit and the rise of between the outlet water temperature and the inlet water temperature; or
b) the mass tlow of the water circulating in the boiler circuit and its temperatu re rise; or
c) the mass tlow and the temperature rise over a secondary heat exchanger corrected by the heat lo ss 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 the mass tlow and the temperature rise of the coo li ng water. The h eat 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 determina ti on of the nominal he at output shall be carried out at a fìring rate such that the output is at l east 100 %, but does not exceed 105 % of the nominal value , a nd the requ ire me nts concerning the nomina l heat sha ll be met If the heat output exceeds 105 %, a second test shall be carried out at a fìring rate between 95 % and 100 % ofthe nominal heat output ofthe boiler.
The actual value for the nomina l heat output shall be determined by Ii near inter polat i on 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 oC and a temperature difference between the tlow and return water temperature of (20 + 2) o 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 oC and 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.
6.3 Determination of the boiler efficiency at nominal heat output The boiler efficiency at nominal heat output is measured as the determination of the nominal heat output (see 6.2). The effìciency shall be determined on the basis ofthe net calorifìc value NCV. The direct method acco rd ing to 6 .5 .4.1 shall be applied.
The indirect method allows an additional check of test accuracy of the test rig to be made by means of an energy balance.
6.4 Performance of testing
6.4.1 General te st condition s
The boiler is installed in accordance with the technical instructions in a we ll -ventilated , draught free room (air speed l ess t han 0 , 5 which h as an am b ient temperature of (20 :t 5) K. The boiler is protected from d irect solar radiation.
T he of the burner shall not be manually changed after adjustmen t. No change sha ll be made to the water flow or any other test parameter during one test period.
The temperature , pressu re and compos i tion of the products of combus tion shall be measured continuously and shall be recorded wit h a samp li ng rate bel ow 10 s.
The flow temperature t l’ and the return temperature tR shall not differ by more than 0 , 5 Kjh x test period [h] at the beginning and the end of the test period.BS EN 304 pdf download.