The low side of a refrigeration system usually houses the evaporator, suction line, and any accessory components located within the suction line. Accessory components can include evaporator pressure regulator valves, suction filters and driers, crankcase pressure regulator valves, and suction accumulators.
The suction inlet to the compressor often contains a screen or filter, which can become obstructed. Even though it seems that the majority of refrigeration system restrictions occur in the high side of the system, service technicians must be aware of evaporator and suction line restrictions and their symptoms when strategically troubleshooting a system.