ISO 22968:2010 pdf free download – Forced draught oil burners.
The burners shall be started 3 mm after switching off, whereby the values of the starting variations in the combustion chamber, at the above-mentioned measuring points, shall reduce within 0,8 s to at least 25 % of the maximum starting value or 0,3 kPa.
Pressure peaks which are less than the combustion pressure but which exceed the maximum starting values by 25 % may occur only during the first 0,5 s. The maximum value of the pressure amplitudes in excess of the combustion chamber pressure is used as reference value.
The behaviour of the burner (i.e. verification of starting amplitudes) shall be recorded by means of a pressure sensor with recording device. The measurement point for the pressures in the combustion chamber shall be on the front plate, above the burner.
The measuring sensor shall be flush with the inner wall of the burner connecting plate. Its length is 250 mm and shall not have an absorptive attenuator. The internal diameter shall be constant up to the pressure sensor.
The measuring system of the pressure sensor up to the record choice shall have a linear frequency range from 0 Hz up to 1 300 Hz. The linearity tolerance shall not exceed 10 % in this range.
6.7.6 Testing during continuous operation in the case of two-stage, multi-stage or modulating burners.
For the test the values for the excess air ratio shown in Figure 1 shall be satisfied and the requirements of 6.1 to 6.7.5 shall be met.
Constant operating conditions pertain if it is established that when carrying out two consecutive measurements, the CO2 content of the combustion gases does not change by more than 0,2 %.
After constant operating conditions have been attained, it shall be checked that
there is no impermissible temperature increase of the components at maximum load at the end of the test,
— no leaks have appeared in the fuel system,
— there is no contamination adversely affecting the safe operation or efficiency of the supervision devices, and
— there is no impermissible post-injection on shut-down. See also Figure 10.
6.7.7 Burners with separate fan
For burners with a separately installed fan, the requirements of 6.7.6 are deemed to have been met if the burner is tested with the maximum size and, where appropriate, with the minimum size, fan and with the selection procedure for intermediate fans indicated in the framework of the type test to the laboratory. A different type designation for the burner is not required in this case.
6.8 Replacement of individual parts and equivalent components
Replacement of individual oil burner parts that have been tested with all the required additional devices as one unit is only possible if they are replaced with equivalent parts. The apparatus then still complies with the requirements of this International Standard (see E.2.4).
Components and subgroups are considered as equivalent replacement parts if it has been established that they have the same safety function and suitability.
6.9 Electrical safety
Examination of the electrical equipment and connections of the burner as specified in 5.1.2.2 shall be carried out visually, by functional test or by measurement.
The burner manufacturer shall provide a detailed declaration of conformity showing that the requirements of 5.1.2.2 have been fulfilled.
The electrical connections for, and the correct integration of, the individual components shall be examined by means of the electrical wiring diagram provided by the manufacturer.