Repair of an ultra-low temperature chiller at −85 °C

The context

Reaching −85 °C is not conventional refrigeration: a single compression stage cannot bridge such a temperature lift. These machines run as a cascade, two nested refrigerant circuits, the first cooling the condenser of the second. Each stage depends on the other, so a drift in one shows up as lost performance across the whole system without an obvious cause. That is what makes diagnosis on this equipment longer than a routine refrigeration call, and why it requires a technician trained on these machines.

What we did

• Full diagnosis of the low-temperature chiller
• Inspection of the cascade / ultra-low temperature refrigerant circuit
• Checks on electrical components and the control system
• Performance testing of the −85 °C cooling system
• Recommissioning and stabilisation of the thermal system