8
The corresponding alarm set points for the Stepped Dose Alarm are given in the table
below.
Flow Range
Required minimum
sensor output
Approximate UVT
0 - 9.9 gpm
11.7 mA
75%
10 - 14.9 gpm
13.1 mA
82%
15 - 20.9 gpm
14.7 mA
90%
21 - 24 gpm
15.8 mA
95%
3.3.3 UV Sensor
Many factors influence a system’s level of UV disinfection, including water quality
(primarily UVT), lamp output, and quartz sleeve fouling. Rather than basing set-points
on any one of these factors, alarm set-points are based on the quantity of light that
actually reaches the sensor. In this way, the UV sensor detects when the water flowing
furthest away from the lamp is no longer being disinfected properly due to any factor.
VIQUA’s UV sensors reliably detect low UV output and identify the need for
maintenance via a 4-20 mA output signal to the controller.
Features
•
Factory assembled and calibrated.
•
UV monitored by a silicon carbide photodiode for long term stability.
