8 | Help with faults
BÜCHI Labortechnik AG
56/70
Operation Manual Pure Chromatography Instrument C-805
Malfunction
Possible cause
Solution
Inconsistent solvent
flow
Loose fitting/air leak into the
pump
u
Find the loose fitting be-
tween mobile phase reser-
voir manifold and pump in-
let fitting and tighten it up.
Liquid leak/pump seals worn
out
u
Fix the leak/replace the
pump seals.
Pump head temperature
reaches solvent boiling tem-
perature, causing the pump to
lose prime and stop flow (this
is likely to occur when running
methods with highly volatile
solvents such as diethyl ether
and methylene chloride)
u
Premix the solvents to re-
duce solvent volatility.
u
Place the highly volatile
solvent bottle in an ice
bath to eliminate boiling.
System pump pres-
sure is higher than
expected
Blocked solvent lines
u
Find the blocked lines and
replace it.
Over-tightened fitting
u
Loosen the fitting or re-
place it.
Blocked columns or fluidic
path
u
Locate the component that
caused the blockage, re-
pair, or replace the compo-
nent.
Leaks
Fitting connection not tight
u
Find the loose fitting and
tighten it up.
Damaged solvent line
u
Find the damaged solvent
line and replace it.
Pump not running
Pump sensor cable becomes
disconnected
u
Locate the cable and re-
connect to the pump sen-
sor.
Pump power cable becomes
disconnected
u
Locate the power cable
and reconnect to the main
board or to the pump.
Incorrect flow path
Incorrect fluidic connections
to/from the mode switching
valve
u
Check/correct the fluidic
connections.
8.4
Faults, possible causes and solutions (fraction collection)
Malfunction
Possible cause
Solution
Liquid not being
collected in fraction
tubes
Incorrect fraction collection
settings
u
Verify that fraction collec-
tion information is set prop-
erly.
Liquid not centered
in fraction tube
Fraction collector is not cali-
brated
u
Recalibrate the fraction
collector.
