Thermo Scientific VH-D20 Operating Manual page 167

High/low gas flow ratio
High backpressure
Negative peaks
Loss of response
Charged Aerosol Detectors (VH-D20, VF-D20)
Operating Manual
Possible Cause
Clogging in the detector
Gas leak
Possible Cause
Nebulizer nozzle/
capillary clogged
Possible Cause
Wrong polarization of
the analog output
Possible Cause
Change in parameters
Drain pump failed
Gas flow turned off
Reduced gas flow
Gas leaking
Remedial Action
Contact Technical Support.
Check the Audit Trail for the respective message. See
(} page 158).
Remedial Action
Poor solubility of analyte during nebulization/analyte build-up.
Check the backpressure of the nebulizer:
1. Remove the nebulizer from the detector. See
Nebulizer (} page 131).
2. Set up a direct flow connection from the pump to the nebulizer.
Make sure no other module is connected in between.
3. Carefully flow liquid through the nebulizer capillary from the
pump. The backpressure of the nebulizer is typically below
10 bars. Liquid should exit the capillary in drops. If the
backpressure rises in the pump, then a blockage is present in the
nebulizer capillary. Contact Technical Support.
To avoid blockage in the nebulizer, always use the detector with
an appropriate mobile-phase composition to maintain solubility.
Remedial Action
Contact Technical Support.
Remedial Action
Check that the detector is turned on and the data acquisition is
on. Check the parameter settings.
Check whether you can hear the drain pump running. If not, the
drain pump may be defective. Contact Technical Support.
Check that the gas flow is turned on in the detector and the gas
supply.
• Make sure that the gas is flowing into the detector.
• Check the nebulizer gas pressure and the gas supply pressure.
• Check gas filter assembly. If necessary, replace the gas filter
assembly. See Replacing the Gas Filter Assembly
Check the gas connections and the gas inlet and exhaust tubes.
Remedy the gas leak and/or replace the gas tubes (see
Disconnecting the Gas Inlet and Exhaust Tubes
8 • Troubleshooting
Messages
Removing the
(} page 134).
(} page 128)).
Page 167