Contherm MITRE 4150 - CO2 Calibration for Infra-Red CO2 Sensor with Front Panel Adjustment

MANUALP/4000_SERVICE_0712 July2012
54
Servicing Procedure:
CO
2
Calibration for INFRA-RED (IR) CO
2
SENSOR
with Front Panel Adjustment
The instruction below demonstrates how to perform the calibration of CO
2
so
that the cabinet displayed CO
2
value reads the same as an external CO
2
meter. Suitably qualified electrical personnel should only carry out this
procedure.
Schedule of servicing:
As and when needed. When the CO
2
sensor, IR board and ZP22 interface
controller board is replaced.
Safety requirement:
Ensure that the cabinet’s power cord is unplugged from the power source
before attempting to remove and replace the CO
2
sensor, IR board and ZP22
interface controller board.
NOTE:
There are 2 types of CO2 calibration:
a. USER Calibration: This is the first on-site calibration check to be done.
This procedure is applicable if the difference in CO
2
reading between the
cabinet display and external meter is within +/- 0.5% CO
2
concentration,
else the factory calibration should be done.
b. FACTORY Calibration: This is initially done in the factory before the
cabinet goes to the customer site. Calibration constants and factors are
written in the manual for initial customer reference. Consequently, do this
procedure whenever the CO
2
sensor, IR CO
2
sensor driver board and
ZP22 interface controller boards are replaced. Do this also when the
USER calibration procedure is not sufficient to correlate the cabinet display
reading and the external CO
2
meter reading.
Servicing Procedure:
1. Connect the external CO
2
meter
on the sampling port and take
note of the external CO
2
meter
reading. Compare this with the
cabinet display. If the difference
in CO
2
reading between the
cabinet display and external
meter is within +/- 0.5% CO
2
concentration, perform the USER
CALIBRATION PROCEDURE.
If the difference is more than
+/- 0.5% CO
2
concentration,
perform the FACTORY
CALIBRATION PROCEDURE.