When the cooling unit fails
A coolant distribution unit, or CDU, helps circulate and control coolant. In a liquid-to-liquid design, its heat exchanger transfers heat between separate equipment and facility loops.
Two pumps can share one weakness
Depends on shared controller or power in this example
Depends on that same component
Both paths may be affected
Draw the shared dependencies
Two pumps may still share power or a controller. Several CDUs may depend on the same facility supply.
A spare unit is useful only if it is ready and capable of taking over. Count the failure paths, not just the installed components.
Separate visibility from operation
Losing the dashboard connection does not automatically mean circulation stopped. A reachable controller does not prove required flow either.
Use the installed system’s documented behavior and measurements.
Failover tests need approved procedures, qualified staff, workload coordination, and stop conditions. There is no safe universal instruction to close a valve or stop a pump.
Try it yourself
Two pumps share one controller power supply. Does that arrangement survive every single failure?
Check your answer
No. The shared supply may defeat the pump redundancy. Establish exactly which failures the design covers and test the required delivered cooling during an approved transition.