The Nelson Sentinel Series Basic Chlorine Sentinel is a complete system that attaches to the drain of a hemodialysis water treatment system sample port. The Basic Chlorine Sentinel detects dissolved chlorine by an auxiliary meter detection technology, self-monitors for maintenance-required conditions, loss of electrical power, as well as two other system conditions such as flooding and the status of RO shutdown alarm. The device chlorine monitoring probe is preferably placed after the second carbon filter, before the RO machine or at the beginning of the patient water treatment loop.The device has three components – a lockable master control enclosure, a lockable probe/tester enclosure, and the remote module installed in the patient area.A chlorine concentration equal to or above the set-point (default: 0.10mg/L) will activate the buzzers and the red CHLORINE alarm indicators for as long as the condition exists. The buzzers can only be muted for 3 minutes (then automatically reset) for as long as the condition exists. The yellow AUTO-TEST OK/CL DETECTED indication will latch. The AUTO-TEST/CL DETECTED indication can be deactivated after the event by pressing the blue RESET PUSHBUTTON on the front cover of the controller.A probe failure or the activation of one of the auxiliary input relays will activate the yellow MAINTENANCE needed indicators as well as the Buzzers which will remain activated as long as the condition exists. However, the buzzers can be muted by the key mute switch while the maintenance issue is being resolved.