BÜCHI Labortechnik AG
Help with faults | 8
Operation Manual Rotavapor® R-300
75/116
Fault
Possible cause
Remedy
Vacuum is not
achieved
Back-evaporation from the re-
ceiving flask
u
Empty the receiving flask
(see Chapter 6.3.2
"Removing the receiving
flask", page 64).
Temperature difference be-
tween vapor and coolant less
than 20 °C
u
Increase cooling (see
Chapter 6.2.3 "Adjusting
distillation conditions",
page 60).
System leaking
u
Check system for leaks (see
Chapter 7.2 "Checking the
system for leaks", page 66).
If using a glass filter pump: wa-
ter pressure of glass filter pump
too low
u
Increase water flow (see
pump operating instruc-
tions).
Vacuum pump too weak
u
Use suitably dimensioned
vacuum pump.
Optimum distilla-
tion not
achieved
Too much back-evaporation
from the receiving flask (espe-
cially with solvent mixtures)
u
Empty receiving flask and
restart distillation (see
Chapter 6.3.2 "Removing
the receiving flask",
page 64, Chapter 6.1.4
"Fitting the receiving flask",
page 52 and Chapter 6.2
"Performing distillation",
page 57).
Other faults in distillation
process (e.g. sudden cooling,
too little heat flow, etc.)
u
Check temperatures of
heating bath and coolant
and adjust as necessary
(see Chapter 6.1.1
"Preparing the heating bath",
page 49 and/or cooler
operating instructions).
u
Lower pressure until distilla-
tion resumes (see vacuum
pump operating
instructions).
