Why is a low condensing pressure problematic in a refrigeration system?

A low condensing pressure can be problematic in a refrigeration system primarily because it affects the operation of the expansion valve. The expansion valve is responsible for regulating the flow of refrigerant into the evaporator. When the condensing pressure is low, the refrigerant condenses at a lower pressure than it typically would, leading to a situation where the pressure difference across the expansion valve may not be appropriate for it to function correctly.

This can result in insufficient refrigerant entering the evaporator, which can disrupt the intended cooling process. If the expansion valve does not feed the refrigerant properly, it could lead to lower refrigerant flow, inadequate cooling, and ultimately reduced efficiency of the entire refrigeration system. In short, the low condensing pressure directly impacts the ability of the expansion valve to perform optimally, resulting in potential issues with cooling performance.

It's clear that while other concerns like power consumption, cooling efficiency, and refrigerant loss are relevant in the context of refrigeration systems, the specific operation of the expansion valve in response to low condensing pressure is a critical factor for ensuring proper system functionality.