Some ice formation is normal, excessive ice indicates a problem.

Normal frost/ice:

  • Thin layer on neck and exterior
  • Forms from moisture in air
  • Typical in humid environments
  • Not a sign of failure
  • Doesn’t affect performance

Excessive ice (problem):

  • Thick ice buildup (>1cm)
  • Ice inside dewar (visible when looking in)
  • Rapid ice formation
  • Ice forming quickly after cleaning

Causes of excessive ice:

  1. Humidity too high – Solution: Improve ventilation, use dehumidifier
  2. Dewar opened too frequently – Solution: Minimize opening frequency
  3. Warm/wet environment – Solution: Move to drier location
  4. Defective gasket – Solution: Replace seal (cost: £50-100)
  5. Vacuum loss – Solution: Professional inspection

What to do:

  1. Remove ice carefully (warm water, don’t use sharp tools)
  2. Improve environmental conditions
  3. Monitor for recurring ice
  4. If ice returns rapidly, seek professional inspection