Description
The "post-purging" option forces purging of the furnace, the flue gas ducts and the flue gas recirculation channel after the burner shut-down. In this way, any residual fuel/air mixture and/or combustion product is blown out. The "post-purging" option forces purging of the furnace, the flue gas ducts and the flue gas recirculation channel after the burner shut-down. In this way, any residual fuel/air mixture and/or combustion product is blown out.
Post-purging only takes place if the ignition, gas or oil valves have been opened and is started immediately after the burner has been shut down. For post-purging, the safety interlock circuit before fan start-up must be closed (e.g. burner swung shut, no fire in the windbox). The air dampers are run to the purge positions, then the post-purge time starts. At the end of the post-purge time, the combustion air fan is switched off and the air dampers are closed.
Post-purging is also carried out in the event of a combustion air pressure or purge position fault.
If the burner is switched on again during the post-purge sequence, the post-purge sequence is aborted and the purge sequence is started from the beginning with all the required safety prompts.
Post-purging with flue gas recirculation is performed in accordance with the parameterization with or without Staged purge sequence.
Post-purging of the furnace is only performed if the "combustion air fan" safety interlock circuit is closed (e.g. burner swung shut and no fire in the windbox).