What happens to the evaporator if there is a disconnect of the external equalizer line during a 5 lb pressure drop?

When there is a disconnect of the external equalizer line during a pressure drop, the evaporator experiences a condition known as starvation. The external equalizer line typically serves to balance the pressure in the evaporator, allowing it to function correctly. This line helps ensure that the pressure sensed by the expansion valve accurately reflects the conditions within the evaporator.

In the event of a 5 lb pressure drop with a disconnected external equalizer, the pressure differential that the expansion valve relies on to regulate refrigerant flow becomes disrupted. As a result, the evaporator may not receive enough refrigerant to absorb the heat effectively, leading to insufficient refrigerant flow. This drop in flow causes the evaporator to starve, which can lead to a decrease in cooling efficiency and potentially cause the evaporator coils to freeze over time as they do not receive the proper amount of refrigerant needed for effective operation.

In summary, the disconnect of the external equalizer line compromises the flow of refrigerant to the evaporator, resulting in starvation, which is the primary impact in this scenario.