Some sounds are normal, others indicate problems.
Normal sounds:
- Slight hissing (pressure relief valve venting)
- Crackling/popping from liquid nitrogen
- Creaking (metal expanding/contracting)
- Gurgling (when being refilled)
Concerning sounds:
- Loud continuous hissing (possible valve issue)
- Whistling (unusual, investigate)
- Banging/clanging (thermal stress, investigate)
- Gurgling when NOT refilling (liquid movement, investigate)
What to do:
- Note when sounds occur (during refill, continuous, etc.)
- Stop using dewar if loud/continuous sounds
- Contact supplier for inspection
- Use emergency backup (dry shipper) while investigating
