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Press ―1‖ YES to lock out the relay during a scheduled feed or press ―2‖ NO to allow the relay to operate
normally during a Calendar Timer.
Note: This setting is only available and visible when the relay is set to operate based on
SETPOINT, WATER METER, or PERCENT of TIME.
13.5 Blowdown by Cycle Setpoint
This option is only available if a conductivity node (NCON) is installed as the MAKEUP COND
input.
If the NIN is installed with a conductivity node installed as the MAKEUP COND input the BLOWDOWN
relay can be configured to blow down based on a cycle setpoint instead of a tower setpoint. The
difference between the two is that a tower setpoint is a fixed conductivity value and does not change with
a change in the makeup water conductivity. A cycle setpoint is the number of cycles of concentration of
the cooling tower water that is desired and will adjust the actual tower setpoint automatically to maintain
the cycles of concentration desired based on the makeup water conductivity. For example: If the tower
setpoint is set to 1000µS, the controller will always try to maintain a reading of 1000 µS in the cooling
tower, no matter the value of the makeup water conductivity. If a cycle setpoint of 3.0 is set, the
controller will always try to maintain a conductivity value in the cooling tower that is 3 times the current
makeup water conductivity.
SETPOINT=
0.0
DEADBAND=
0.00
To set up the blowdown relay to operate based on a cycle setpoint, select BY CYCLE SETPOINT. The
following screen will appear.
The setpoint is the number of cycles of concentration you want to maintain. The deadband is the
number of cycles to use as the deadband. Refer to section 13.8 for a discussion on setpoint, deadband,
and blowdown timeout.
Use the keypad to enter a cycles of concentration setpoint. Press ―ENT‖.
Use the keypad to enter a deadband value. Press ―ENT‖.
Use the keypad numbers to enter the time in hours and minutes before the blowdown timeout
alarm will appear and press ‖ENT‖. Maximum setting is 17 hours and 59 minutes.
The next screen is the ―WHEN TO ACTIVATE‖ screen. Select ―1‖ ABOVE SETPOINT to turn on
the blowdown relay when the conductivity rises above the cycles of concentration setpoint, or
select ―2‖ BELOW SETPOINT to turn on the blowdown relay when the conductivity falls below
the cycles of concentration setpoint
13.6 By Multi-Setpoint
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