What might cause an evaporator that is chilling liquids to not cool properly if the superheat is set normally?

When dealing with an evaporator that is not cooling properly despite having the superheat set correctly, one potential issue lies with the circulator. The circulator is responsible for moving the fluid through the system, including the evaporator. If the circulator is malfunctioning or is not operating efficiently, it can lead to insufficient fluid flow over the evaporator coils. This inadequate circulation can prevent the refrigerant from absorbing sufficient heat, leading to poor cooling performance.

In contrast, an overcharge of refrigerant could cause issues like flooding or liquid refrigerant entering the compressor, while an undercharge typically results in a lack of refrigerant to absorb heat. The thermostatic expansion valve (TEV) could also impact cooling, but if the superheat is set correctly, it indicates that the TEV is likely functioning adequately in terms of refrigerant flow. The circulator's role in ensuring proper flow and heat exchange is crucial; without it, even a well-tuned evaporator will struggle to provide the necessary cooling effect.