2
3. LCD Display Symbol
Symbol
Meaning
Description
CO2
Concentrati
on ppm
(Parts Per
Million)
Ambient CO2 Concentration
Alarm
Alarm Icon
DIAG
Diagnose
Test communications between
the SEU and RDU (see 9.1)
AL1
CO2 5,000
TWA
Relay 1 will trigger when CO2
concentration exceeds
5000ppm TWA (Time
Weighted Average). The AL1
(Red 1 LED) will flash but
buzzer will not sound. (see
9.2)
AL2
2
nd
CO2
Alarm Level
Relay 2 will trigger when CO2
concentration exceeds the 2nd
alarm level. (Preset at
15,000ppm). The AL2 (Red 2
LED) will flash. The buzzer will
sound. (see 9.3)
AL3
3
rd
CO2
Alarm Level
Relay 3 will be triggered when
CO2 concentration exceeds
the 3rd alarm level. (Preset at
30,000ppm) The AL2 (Red 2
LED), AL3 (Red3 LED), and
Fault LED will flash. The
buzzer will sound. This status
will be latched. (see 9.4)
CALI
Calibration
To calibrate the CO2 sensor
when the accuracy deviates
from the actual CO2
concentration. (see 9.5)
RCFS
Recover
Factory
Setting
To recover factory default
settings and remove any
customized settings. (See 9.6)
Hi
High
CO2 concentration is above
5% (50,000 ppm)
Fan Icon
CO2 levels exceeds Alarm2,
the fan icon will appear. If
connected via Relay 2, this
would turn on a ventilation fan.
