Parallel Indoor Heat Exchanger Isolation During Refrigerant Pump-Down

The patent segments the refrigerant collection process by identifying and separating the leaking indoor heat exchanger from non-leaking ones. The control device closes isolation valves for non-leaking indoor heat exchangers, dividing the collection task into focused segments rather than treating all units uniformly. This segmentation enables parallel processing where leaking units are collected while non-leaking units are isolated, resolving the contradiction between complete recovery and time efficiency.

The patent applies partial action by performing refrigerant collection only from heat exchangers that actually need it (leaking units) rather than from all units excessively. The control device determines which indoor heat exchangers require collection based on leak detection, and selectively activates collection for those units while isolating others. This partial approach achieves sufficient refrigerant recovery without the excessive time cost of collecting from all units.

The patent introduces isolation valves at strategic segmentation points in the refrigerant circuit to enable selective isolation of non-leaking indoor heat exchangers. These valves create controllable segments that can be independently managed during pump-down operations. The segmentation approach balances the added device complexity with the benefit of reduced collection time by enabling parallel isolation and collection operations.

The control device acts as an intermediary that manages the complexity of coordinating isolation valves and collection operations. It processes leak detection information, determines which units require collection, and orchestrates the timing of valve operations. This intermediary control layer absorbs the system complexity while presenting a simplified operational interface, enabling time-efficient pump-down without overwhelming system complexity.