Water Flow Switch Doesn't Work?

This is a good one!  The other day we were contracted to connect of of our central station monitored fire alarm systems to a new EST-2 panel installed for a separate tenant.  No big deal, install a couple of addressable monitor modules and relays and done.

Well when the other fire alarm company was conducting their EST-2 system test we got a good laugh.  Keep in mind that this is a very large Southern California based fire alarm installation contractorr I am referring to and will not disclose names for obvious reasons.

Now the water flow switch is monitored trough our fire alarm system and then reports to the EST-2 through a relay contact.  One of their three technicians opened the main drain on the riser just below the water flow switch and proceeded to time the response.  Sound strange?  Yeah, exactly the main drain below the switch!  Out of the three technicians from this large company not one could figure out why the switch never initiated an alarm.  After about 2 minutes he shut the drain valve and told the owner of the site that the water flow switch was bad and needed to be replaced.

At this point one of my service technicians on site stepped in and told him the switch was fine and it might help if he tried the inspector's test valve located at the end of line.

It still amazes me that these people are in the industry.  Its not like we are painting walls.  We are installing systems designed to save lives and if technicians like this are installing them, WATCH OUT!!