Dear Sirs.,

I have he same problem (NOx value is *********) and in the log it says that the autocal drift beyond tolerance, but that is not true. I have a drift of 1-2% and the limit is 10%.

like in the following post: https://support.industry.siemens.com/tf/ww/en/posts/ultramat-23-no-gas-reading-after-autocal/67547/?page=0&pageSize=10 

We have 2 Ultramat 23 and it happened in both already. The first one was replaced by the Siemens warranty, we got a new equipment, but now for the second one the warranty is over.

How do I know if the problem is with the IR Source, the  CH4 detector or contamination of the analyzer cell?

Thank you in advance

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Split from ULTRAMAT 23 SO2 ******** FAULTY READING.

Dear Sir

With U23 , to confirm the source and detector performance the best way is to check R & V values.

Run the Analyzer with Nitrogen and go to  following functions. Analyzer Status >> Diagnostic Values >> IR Diagnostic values >> Lock-in ADU + ADU >> Select the components channel number >> Check R & V values.

R and V values should be around 500000 ( this values we will get if it a new detector) . Generally a detector will not respond less than 280000 units and results in autocal drift beyond tolerance alarm.

If the above values are less than 280000 , I would suggest to clean the chamber and recheck it , if still its the same than we need to change the detector cell including the gain resistor.

I hope the information is helpful.

Regards

Ravindran

Siemens LLC , Dubai

Dear Sir,

I have same problem with my Ultramat 23.

SO2 value is "******"

Fault status : Autocal-Drift beyond tolerance

After i checked R-V values :

NO-R : 612580 ; NO-V : 612729

CO-R : 466495 ; CO-V : 466495

SO2-R : 869315 ; SO2-V : 869311

You said before "Generally a detector will not respond less than 280000 units and results in autocal drift beyond tolerance alarm". But on my case, i have R-V values of NO, CO & SO2 components still around 500000. it means IR source in good condition right?

What procedure should i do to confirm which part is in problem?