Teledyne t320u Manuale Utente

Troubleshooting and Service 

Teledyne API – Model T300/T300M CO Analyzer 

4.  Too many analyzers on the manifold.  This can cause either a slope or offset error 

because ambient gas with its pollutants will dilute the zero or span gas.   

12.3.2. NON-REPEATABLE ZERO AND SPAN 

As stated earlier, leaks both in the T300/T300M and in the external system are a 
common source of unstable and non-repeatable readings. 

1.  Check for leaks in the pneumatic systems as described in Section 11.3.3.  Don’t 

forget to consider pneumatic components in the gas delivery system outside the 
T300/T300M such as: 

  A change in zero air source such as ambient air leaking into zero air line, or; 
  A change in the span gas concentration due to zero air or ambient air leaking 

into the span gas line. 

2.  Once the instrument passes a leak check, perform a flow check (see Section 11.3.4) 

to make sure adequate sample is being delivered to the sensor assembly. 

3.  A failing IR photo-detector may be at fault.  Check the CO MEAS and CO REF test 

functions via the front panel display to make sure the signal levels are in the normal 
range (See Appendix A) and are quiet. 

4.  Confirm the sample pressure, wheel temperature, bench temperature, and sample 

flow readings are correct and have steady readings. 

5.  Disconnect the exhaust line from the optical bench near the rear of the instrument 

and plug this line into the SAMPLE inlet creating a pneumatic loop.  The CO 
concentration (either zero or span) now must be constant.  If readings become quiet, 
the problem is in the external pneumatics supplies for sample gas, span gas or zero 
air. 

6.  If pressurized span gas is being used with a zero/span valve option, make sure that 

the venting is adequate. 

12.3.3. INABILITY TO SPAN – NO SPAN BUTTON (CALS) 

1.  Confirm that the carbon monoxide span gas source is accurate; this can be done by 

switching between two span-gas tanks.  If the CO concentration is different, there is 
a problem with one of the tanks. 

2.  Check for leaks in the pneumatic systems as described in Section 11.3.3. 
3.  Make sure that the expected span gas concentration entered into the instrument 

during calibration is the correct span gas concentration and not too different from 
expected span value.  This can be viewed via the CONC submenu of the Sample 
Displays. 

4.  Check to make sure that there is no ambient air or zero air leaking into span gas 

line. 

12.3.4. INABILITY TO ZERO – NO ZERO BUTTON (CALZ) 

1.  Confirm that there is a good source of zero air.  Dilute a tank of span gas with the 

same amount of zero air from two different sources.  If the CO Concentration of the 
two measurements is different, there is a problem with one of the sources of zero 
air. 

2.  Check for leaks in the pneumatic systems as described in 11.3.3. 
3.  If the analyzer has had zero/span valve options, the CO scrubber may need 

maintenance. 

4.  Check to make sure that there is no ambient air leaking into zero air line. 

06864B DCN6314