130  AO2000 CONTINUOUS GAS ANALYZERS  |  OI/AO2000-EN REV. B 
 
 
 
6  The following status messages are active during the heating-up phase: 
"Operating temperature": the temperature of the detector has not yet 
reached the threshold. 
"Flame error": the flame has not yet ignited. 
"Temperature limit value 1, 2": the temperature of the detector (T-Re.D) 
and possibly of the heated sample gas connection (T-Re.E) is over or 
below the upper or lower limit value 1 (2). 
"Pressure limit value 1, 2": the pressure at one of the internal pressure 
regulators for instrument air (inlet, outlet), combustion air (air) or 
combustion gas (H2) is over or below the upper or lower limit value 1 (2). 
7  As soon as the temperature of the detector reaches the threshold value 
(150 °C) the corresponding solenoid valve in the analyzer module auto-
matically switches off the instrument air. The negative pressure regula-
tion and the combustion air regulation attempt to adjust the pressures 
to the respective set point.   
The sample gas begins to flow through the analyzer after the instrument 
air is connected. 
8  After the pressures have been adjusted to the respective set point, the 
respective solenoid valve in the analyzer module automatically connects 
the combustion gas. The combustion gas regulation attempts to adjust 
the pressure to the set point. 
Adjustment of the controlled variables of the internal pressure regula-
tors 
If the analyzer module is not automatically put into service with the 
pressure values specified in the analyzer data sheet, the controlled vari-
ables of the internal pressure regulators must be adjusted. If the con-
trolled variables of the internal pressure regulators deviate, the inlet 
pressures of instrument air, combustion air and combustion gas must 
be changed (steps 9 to 11). 
9  Instrument air: use the external pressure regulator to set the controlled 
variable for Outlet to approx. 60 % (max. 70 %). 
Controlled variable too high  reduce pressure. 
Controlled variable too low  increase pressure. 
(The controlled variable for Inlet depends on the sample gas flow 
rate.) 
10  Combustion air: use the external pressure regulator to set the controlled 
variable for Air to approx. 55 % (max. 60 %). 
Controlled variable too high  reduce pressure. 
Controlled variable too low  increase pressure. 
11  Combustion gas: use the external pressure regulator to set the con-
trolled variable for H2 to approx. 42 % (max. 52 %). 
Controlled variable too high 
 increase pressure. 
Controlled variable too low  reduce pressure.