CIRAS-3 Operation Manual V. 1.09  175  support@ppsystems.com 
 
2
The DIFF BAL value for H2Or is > 0.5 mb.  Typically 
this is due to inaccurate recalibration or deterioration 
of the internal sample cell due to dust, dirt, water.  It 
might just be a transient message that disappears 
and if it does you are ok.  If the message does not 
disappear after 5-6 seconds perform a manual Diff 
Bal (Z-Diff Bal F7) > Zero).  If problem persists 
contact PP Systems.  Also ensure that all desiccants 
are fresh and that the absorber columns are firmly 
seated in their respective manifolds. 
Cuvette Flow 20% out from set value 
[91] 
Normally this is just a transient and the message 
disappears after 5 or 6 seconds and is quite 
common after a change in flow rate.  If the message 
does not disappear check for restrictions in the gas 
circuit associated with the ASU pump (kinked 
piping).  
Exhausted chemicals in the Zero column.  Replace 
soda lime, Drierite and especially the Molecular 
Sieve. 
Board supply voltage < 6.4 V [93] 
Internal battery(s) are low.  Charge the battery(s) 
using the power supply adapter provided by PP 
Systems. 
Flow Rate through the Reference Cell 
too High [94] 
Check the reference pump (including electrical 
connection) and any kinks that might be causing 
restriction.  Clean or replace the reference pump.  
See 
Servicing the Air Sampling Pump (Reference & 
Analysis). On page 181.  Also check that the Zero 
and CO
2
/H
2
O control manifolds are properly seated 
in their respective manifolds and all associated “O” 
rings are not pinched off or cracked. Also check the 
internal hydrophobic filter.