Teledyne 202 Manuel D’Utilisation

 

Page 20 of 24

 

 

CAUSE:  Plugged orifice. 

ACTION:  Verify the presence of a 10-50 psig pressure across the instrument.  If present, shut off gas 

supply and power supply.  Remove orifice per Section 4.9.  Examine orifice.  If plugged, clean or replace 
as applicable.  Reassemble valve. 

 

SYMPTOM:  Flow meter reads other than 0.00 VDC with no flow, or there is a small flow when flow 

meter reads 0.00 VDC. 

CAUSE:  ZERO potentiometer is out of adjustment. 

ACTION:  Shut off all flow.  Adjust ZERO potentiometer until output reads 0.00 VDC. 

 

SYMPTOM:  Flow meter out of calibration and nonlinear. 

CAUSE:  Leaks in gas inlet or outlet fittings. 

ACTION:  Check all fittings for leaks by placing soap solution on all fittings between gas supply and final 
destination of gas.  Check flow meter for leaks.  Replace “O” rings if required or recalibrate as necessary. 

5) 

NOTE:  Steps 5 and 6, adjusting the SPAN pot and performing a calibration run, will require the use 
of a calibration reference. 

1) 

Connect power cable to D connector as specified in Section 

2.7.  Allow instrument to warm up for 30 minutes with 10% 
flow and instrument in AUTO position. 

2) 

After the warm up period, set the flow to zero and insure 

that, indeed, there is zero flow. Wait for 2 minutes. 

3) 

Set ZERO (R13 on 15 Volt / R20 for 24 Volt) potentiometer 

for 0.000 VDC output. 

4) 

Turn on gas supply to inlet of instrument.  Use the Valve 
Override CLOSE feature or, if Valve Override is 

unavailable, give the controller a command of zero.  Adjust 
the orifice underneath the controller to obtain zero flow.  If 

the Valve Override feature was used to close the valve, set it 
to AUTO.  Ensure that full range flow can still be obtained 

at minimum inlet pressure. 

5) 

NOTE:  Perform this step only if a calibrated flow reference 
is available.  Set command to 100%.  Adjust SPAN (R18 on 

15 Volt / R2 for 24 Volt) pot until the flow reference reads 
full scale flow (5.000 VDC). 

6) 

 Record flow meter and flow reference outputs for flow rates of 20%, 40%, 60%, 80% and 100%. 

Figure 4.1