How to calibrate the flue damper after replacing the positioner?
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The locator for the flue damper is broken. After replacing it with a new one, it’s necessary to recalibrate the valve position. The instrument technician said that the flue damper needs to be moved to its fully open and fully closed positions twice automatically. The problem is that it’s not possible to do this during a shutdown for maintenance; if such a thing were done, the furnace would go out immediately. Do any of you know how to handle this situation?
During maintenance, it is best for someone to go into the flue gas mixing chamber to take a look; when the flue dampers are closed, those outside should make notes and adjust the indicator pointer
Do not turn it to full on or full off; after replacing it, set the signal to 50% first, and then adjust it up or down depending on the condition of the furnace. After all, as long as the heating furnace is in operation, the transmitter cannot be in a fully open or fully closed state. Adjust it after the work stops to resolve the issue completely
I’m not sure what the flue gas flow pattern is in your heating furnaces; generally, it’s possible to have it fully open or fully closed, but it depends on the specific setup
That’s exactly what we do, but this results in a slight discrepancy between the valve position indicated by the flue damper positioner and the actual valve position. Is there a better way?
This can be done during maintenance, but it’s currently in operation
There are significant risks during operation; it’s necessary to proceed slowly and pay attention to the negative pressure in the furnace
Since the deviation is known, it’s sufficient to identify that value and ensure the furnace operates properly; after all, the flue dampers are not adjusted frequently, so it can be dealt with once production stops
The deviation is not fixed, and sometimes the action is taken and sometimes it isn’t; better online solutions are sought