One follow up question: Is the flow alarm part of the chiller system or is it a third party part?
It's a little hard to explain.
First they had a large closed loop cooling water system for a laser lab in a nearby building. It had it's own pump and flow alarm. But this system had a huge excess cooling capacity.
So because we needed a building closed loop water cooling system for our e-beam instruments, they added a *new* closed loop connected to the first one through a heat exchanger, again with it's own secondary pump- but at first they forgot to add a separate flow alarm for this new secondary closed loop cooling water system.
When that secondary loop pump failed (Murphy's Law), there was no alarm until some of the instruments started complaining about the water inlet temperature to the individual instrument chillers.
So they added a second flow alarm to the secondary closed loop pumping system and now all is fine.
I don't know anything about the specific flow alarm systems they used (it was a facilities issue), but I expect they are just off-the-shelf items.
john
On a slightly related note, the "Sensaphone" units we use for calling us when there's a power failure (or the P-10 gas drops below 500 psi):
http://probesoftware.com/smf/index.php?topic=752.msg4686#msg4686also have a number of "built-in" alarms... for example, a loud noise alarm (using a built-in microphone), and a water flood alarm (using a small water sensor that sits on the floor).
Both have been separately triggered by various appropriate equipment failures and hence saving us much cost and repair work!
john