Bruker 600'54 Ascend ULH, User Manual

Page: 42 / 102

42 ZTKS0175 / Z31991 / 03
Troubleshooting
6.2.3 During Cooling Down
a. see note on page before
Continued on next page
Indicator Possible reason Solution By
Cooling with liquid
nitrogen continues
too slowly. Empty transpor-
tation dewar. Refill or replace transportation
dewar. Bruker Service
Transfer pressure
too low. Increase transfer pressure
slightly (max. pressure
0.3 bar). Bruker Service
Transportation
dewar is leaky; no
transfer pressure
can be applied. Check transportation dewar
and replace if necessary. Bruker Service
Precooling with
liquid nitrogen
continues too
quickly. Transfer pressure
too high. Stop cooling. Adjust correct
transfer pressure. Bruker Service
Vacuum in RT
vessel does not
reach
5 x 10
-5
mbar in
48 hours.
O-rings may be
leaky. Check and clean O-rings and
slots; replace O-rings if
necessary:
•
of the Vacuum Valve
• of the drop-off plate
• of the reduction and
sealing flanges
• of the bottom plate
a
Bruker Service
O-rings may be
frozen due to contact
with liquid nitrogen.
1. Stop cooling.
2. Warm up O-ring with
warm air
3. Wait until the vacuum is
recovered.
4. Prevent liquid nitrogen
from splashing on
O-rings.
Bruker Service
Defective pumping
unit or pumping line. Check pumping unit and
pumping line:
A vacuum less than 10
-6
mbar
must be reached with a
closed sealing plug.
Replace if necessary.
Bruker Service