Troubleshooting the CryoStat
See also: |
Frost or ice accumulates around the outside of the cryostat in the area of the sample well
Cause: | The internal vacuum is degrading and must be re-evacuated. |
Action: | Effective re-evacuation can be done only when the cryostat is warm, such as after an analysis. It is recommended that the vacuum pump always remain powered ON. |
Elevator tries to rise
Cause: | Analysis program is not set to enable the cryostat. |
Action: | In the analysis program, go to Unit [n] > Enable CryoStat and ensure that this option is selected. Failure to do so will cause the P0 port to be evacuated and the elevator will try to rise. |
Valve motor in cryostat cold head does not start when the compressor starts
Cause A: | Cold head cable is not connected. |
Action A: | Stop the compressor. Connect the cable. |
Cause B: | Open circuit in the cold head cable. |
Action B: | Disconnect the cold head cable. Check each conductor for continuity. Replace the cable if necessary. |
Cause C: | Defective valve motor. |
Action C: | Contact your Micromeritics Service Representative. |
Cause D: | Blown fuse in the compressor's electrical box. |
Action D: | See the manual supplied by the compressor manufacturer. |
Valve motor in cryostat cold head hums but does not start
Cause A: | Valve disk has stalled. |
Cause B: | Defective valve motor. |
Action B: | Contact your Micromeritics Service Representative. |
Cause C: | Open circuit in the cold head cable. |
Action C: | Disconnect the cold head cable. Check each conductor for continuity. Replace the cable if necessary. |
Valve motor on the cryostat cold head runs but there is no cooldown
Cause A: | No insulating vacuum. |
Action A: | Check the vacuum system for operation and leaks. |
Cause B: | Gas line couplings are not fully engaged. |
Action B: | Ensure all couplings are fully engaged and torqued. |
Cause C: | Gas lines are connected incorrectly. |
Action C: | Reconnect the gas lines. See the manual supplied by the compressor manufacturer. |
Cause D: | Compressor output is inadequate. |
Action D: | Troubleshoot the compressor. See the manual supplied by the compressor manufacturer. |
Shroud is sweating or abnormally cold
Cause: | Loss of insulating vacuum. |
Action: | Check the vacuum system for operation and leaks. |
Abnormally noisy operation after a sustained period of five to fifteen minutes
Cause A: | Incorrect compressor pressures. |
Action A: | Troubleshoot the compressor. See the manual supplied by the compressor manufacturer. |
Cause B: | Contaminants in the gas. |
Action B: | Perform Gas Cleanup and Recharging procedure on the cold head, compressor, and the gas lines. See the manual supplied by the compressor manufacturer. Contact your Micromeritics Service Representative. |
Intermittent operation
Cause: | Compressor is cycling on and off. |
Action: | Troubleshoot the compressor. See the manual supplied by the compressor manufacturer. |
Temperature is cycling
Cause: | Contaminated gas is causing a cold head freezing-thawing cycle. |
Action: | Perform Gas Cleanup and Recharging procedure on the cold head, compressor, and the gas lines. See the manual supplied by the compressor manufacturer. Contact your Micromeritics Service Representative. |
Sudden loss of refrigeration capacity
Cause A: | Loss of insulating vacuum. |
Action A: | Check the vacuum system for operation and leaks. |
Cause B: | Compressor malfunction. |
Action B: | Troubleshoot the compressor. See the manual supplied by the compressor manufacturer. |
Slow loss of refrigeration capacity
Cause A: | Small insulating vacuum leak. |
Action A: | Leak check and repair the vacuum system. |
Cause B: | Worn seals in the cold head. |
Action B: | Contact your Micromeritics Service Representative. |
Cause C: | Cold head is leaking. |
Action C: | Contact your Micromeritics Service Representative. |
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