10
Maintenance
Operating Instructions | symphony 5.3 A – 06/2009
10
Maintenance
10
Maintenance
56
10.5 Preparing the CO
2
calibration
To determine the exact measured value of the device-
integral CO
2
sensor, a CO
2
comparison measurement
may be performed every three months.
If a major deviation is found during this check, a CO
2
calibration is required.
During this process, the CO
2
control of the device is
set to the value measured during the comparison
measurement.
Use a calibrated measuring instrument with an accu-
racy of
± 0.3 % CO
2
for this test.
Suitable instrument:
• Portable IR readout instrument. (Part no. see Sec-
tion 11, “Parts and accessories”)
The measuring sample is withdrawn through the
sealable measurement opening of the glass door or
through the access port at the rear panel of the device.
The comparison measurement must be performed
when the device is completely stable.
Comparison measurement procedure:
1. Turn device on using power switch.
2. Set CO
2
nominal value and allow device to heat
up completely and to create humidity. This pro-
cess may take several hours.
A
3.
Fig.20:
Route the measuring instrument either
through the measurement opening [2] in the glass
door or through the access port [1] at the rear
panel of the device. Wait until the CO
2
value dis-
played by the instrument has stabilized.
4. Remove measuring probe, plug measurement
opening and close doors.
5. Calibrate CO
2
control as described in Section
10.6.
Measurement example:
• CO
2
nominal value: 5 %
• Measured value: 5.6 %
NOTE!
Excessive CO
2
content:
Excessive CO
2
content after the calibration
can be reduced by leaving the device doors
open for approx 30 seconds!
1
2
Fig.20: CO2 calibration
