Thermo Scientific Mercury Freedom 80i Manual page 54

Troubleshooting
System Troubleshooting Guides
4-8 Mercury System Manual
Malfunction
Instrument or system
appears to zero, but there is
weak or no response to
span gas.
Possible Cause Action
less when the lamp is OFF, the
problem may be caused by scattered
light from dust in the optical bench.
Input board failure Disconnect the input board from the
interface board by unplugging ribbon
cable labeled "INPUT." The instrument
reading should drop to zero or to a
negative value.
Critical orifice Check/clean orifice.
blocked
External pump failure Replace the external pump.
Insufficient air to 81i Check the source pressure to the 81i.
The pressure should be 30 psig.
Calibration system Check solenoids or other hardware to
failure be sure that span gas is being
delivered to the correct spot.
Flow rate of the Verify that the zero air system is
diluted span mix is providing adequate flow.
inadequate
Critical orifice Check/clean orifice.
blocked
Instrument is not Check sample flow and pressure
drawing in span gas readings (Diagnostics menu).
Use an independent flow meter to
check flows at the span inlet and
exhaust bulkheads (they should
match).
Perform a leak test.
Hg is being absorbed Replace any lines made of vinyl or
by tubing, filters, or other plastics with fresh Teflon.
dirt in the calibration
Replace Teflon filter membranes that
system
look dirty. Remove any filters that are
not Teflon membranes.
Lamp failed Check the lamp intensity (Diagnostics
menu) and voltage.
81i output problem Check 81i to verify output
concentration.
PMT or input board With previous coefficients and PMT
has failed voltage known, introduce a known
concentration of span gas.
Hydrator gas leak or Check to see if bottom reservoir has
no water water. Locate gas leak and repair.
Thermo Fisher Scientific