KST – KROMSCHRÖDER SYSTEM TECHNOLOGY
Equipment fitted with forced or induced draught burner(s) shall be fitted with devices for proving adequate air flow during the pre-purge, ignition and operation of the burner. Air flow failure at any time during the pre-purge, ignition or operation of the burner shall cause safety shut-down and, in the case of no operator supervision, shall cause a lockout.
This function shall meet the requirements of the protective system according to 5.7.2 and 5.7.3.
The air-proving device shall be checked in the ‘no flow’ state prior to start-up (e.g. by stopping the combustion air supply or by interrupting the air signal to the device(s) in such a way as to simulate stopping the combustion air supply). Failure to prove the device in the “no flow” condition shall prevent start-up. [Footnote 1]
Air flow shall be monitored:
- by pressure detectors or
- by flow detectors.
It has to be shown that any of these devices provide satisfactory and reliable proof of the flow for all operating conditions.
This requirement shall not apply to portable gas burners, work station burners and equipment-integrated burners with open flame, supervised continuously by trained operators, and having a maximum burner input rating below 70 kW.
Air pressure detectors shall comply with EN 1854.
The following chapters are printed with the permission of the DIN Deutsches Institut für Normung e.V. (German Institute for Standardization). For the implementation of the DIN Standard, the version with the most recent issue date is deemed authoritative. This is available from Beuth Verlag GmbH, Burggrafenstrasse 6, 10787 Berlin, Germany.
Our note on this Standard:
1) The Air min. air pressure switch must be scanned for contact changeover when the fan starts. If there is a fan on the burner side, it is possible to intervene in the fan control for this purpose. Otherwise, we recommend an upstream 3/2-way valve.