Troubleshooting the CryoStat

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.
 
   Micromeritics Learning Center    Contact Us

Copyright © 2014 - 2018. Micromeritics Instrument Corporation. All rights reserved.