5-2
Chapter 5: Gas Analyzer Start-Up
42/24-10 EN Rev. 9
Gas Path and Housing Initial Purge
Take note of the instructions in the “Housing Purge” section, page 3-12.
Purge Prior to
Start-Up
The gas paths and if necessary, the system housing should be purged prior to
starting the gas analyzer.
First this ensures that the gas paths and system housing are free from contami-
nants (e.g. corrosive gases) and dirt on start-up.
Second this prevents the possibility of an explosive gas/air mixture being present
in the gas paths or system housing when the power supply is connected.
Purge Gas Supply
Requirements
Nitrogen or instrument air should be used as purge gas (refer to the “Purge Gas
for Housing Purge” section, page 1-6, for detailed information).
Purge Gas Flow and
Duration of Purge
Process
The purge gas flow and the duration of the purge process depend on the volume
to be purged (see the following table). If the purge gas flow rate is lower than
indicated the duration of the process must be increased correspondingly.
Volume to be Purged
Purge Gas Flow Rate
Duration
Gas Path
100 l/h (max.)
approx. 20 sec.
Central Unit with or without
Analyzer Module
200 l/h (max.)
approx. 1 hr.
Caldos25, Caldos27, Magnos206,
Magnos27 (analyzer separately)
200 l/h (max.)
approx. 3 min.
The purge gas flow rates given in the table only apply to the initial purge. During
operation other values apply (see “Operation” section, page 5-5).
CAUTION!
Purge gas can escape from the housing if there are any leak points. When
using nitrogen as the purge gas, take all required precautions against
suffocation.
CAUTION!
Purge gas flow must always be restricted upstream of the purge gas inlet!
If the purge gas flow is restricted after the purge gas outlet, the housing
seals are subjected to full purge gas pressure which can result in damage
to the keypad!
