Advanced
®
Cryoscope Model 4250 User’s Guide
8
6. Press the STOP key a second time to exit from the test menu to
“Press START to Continue”.
Step 8 — Run a diagnostic test
With a sample tube containing fluid such as a calibration standard or
deionized water in the freezing chamber, press the START key. The
microprocessor will respond with the display, “Running Diagnostics”,
while it lowers the operating head, cools the freezing chamber and com-
pletes a series of internal diagnostic checks. If the diagnostic checks are
not successfully completed or the freezing chamber does not cool prop-
erly, a diagnostic message will be presented.
NOTE Any error reported prior to or during diagnostics will require
the operator to press STOP before any of the keyboard com-
mands can be used.
Primer Pump
Fluid Return
Tube
Figure 4: Prime the Heat Transfer Fluid Pump