My understanding is that the narrow line attached to the seawater intake that leads several feet above to some kind of sensor is there to detect blockage and trigger the "filter eau mer puisard" light and alarm in the companionway on my SM2K. I've been unable to trigger this alarm, for instance by closing the seacock and running one of the pumps. I'm concerned it may not be working.
Does anyone have any information on this sensor/alarm, such as around testing its operation?
Thanks in advance,