Operation - Macurco CD-12 User Instructions

Operation

1. With the display function turned "On", the CD-12 will show the current concentration of CO2 ppm in the air. Normal outdoor
concentration ranges between 350-450 ppm. When the CO2 concentration reaches the Fan Relay setting (1000ppm, for
example) the display will flash back and forth between "FAn" and "1000". With the display function turned "Off", the display
does not show the CO2 concentration, but will show "FAn" as long as the fan relay is activated.
2. With the display function turned "On" and the CO2 concentration reaching the Alarm Relay setting, (2000 ppm, for example) the
display will flash back and forth between "ALr" and "2000". The buzzer will sound indicating "Alarm" if the buzzer is turned "On".
With the display function turned off the display does not show the CO2 concentration, but will show "ALr" when the Alarm relay
is activated.
3. With the 4-20 mA function turned "On" and the CO2 concentration climbing, the 4-20 mA signal will ramp up corresponding to
the concentration (0-2000 ppm, for example). The display will show "FAn" and "ALr" and sound as outlined above.
Default Configuration – Factory Settings

The default Power Up Test setting is On

The default Display setting is On

The default Buzzer setting is On

The default Alarm Relay Setting is activation at 2000 ppm

The default Alarm Relay Configuration setting is Normally Open

The default Fan Relay Setting is activation at 1000 ppm

The default Fan Relay Delay setting is 3 minutes

The default Fan Relay Minimum Runtime setting is 0 minutes

The default Fan Relay Latching condition is OFF

The default Trouble Fan Setting condition is OFF

The default 4-20mA Output setting is On
To change settings, remove the Philips screw on the front of the CD-12. Pull off the front cover of the unit.
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