Emerson Process Management 760004-A - Manual (Page 68)

Instruction Manual
760004-A
February 2002
5-2 Troubleshooting Rosemount Analytical Inc. A Division of Emerson Process Management
Model NGA 2000 HFID
18. Verify that there is +10VDC to the
reference thermistor.
c. Drift
1. Verify that the sample, burner air, and
fuel supply pressures are constant.
2. Check that the tubing, regulators,
pumps, fittings, and valves are clean
of hydrocarbons.
3. Verify that the oxygen level in the
burner air and sample are constant.
4. Verify the THC level is correct for the
burner air and fuel supply.
5. Check that the ambient temperature
is changing <10 °C per hour.
6. Verify the burner is clean.
7. Verify temperature of the sample gas,
case, burner, and oven has stabilized.
8. Verify the Preamp PCB is clean.
9. Verify atmospheric pressure at burner
exhaust is constant.
10. Verify purge gas pressure is constant.
11. Verify burner has been on and stabi-
lized.
12. Check for gas leaks.
d. Noise
1. Check that the burner exhaust is free
from water condensation.
2. Verify connection to the collector is
correct.
3. Verify connection to the polarizing
voltage is correct.
4. Check the ambient temperature is
changing <10 °C per hour.
5. Verify the +24VDC is clean and
grounded properly.
6. Verify there are no strong magnetic
fields near.
7. Check for excessive vibration.
8. Verify burner exhaust is vented to a
constant atmospheric pressure.
9. Verify bypass line is vented to a con-
stant atmospheric pressure.
10. Verify purge out port vented to a con-
stant atmospheric pressure.
11. Verify the collector wires are routed
away from the heater.
12. Verify the collector wires are clean
and not damaged.