Air Conditioning Certification (A-02) Practice Exam 2026 – Your All-in-One Guide to Exam Success!

An increase in head pressure within a refrigeration system leads to a rise in the pressure of the refrigerant entering the capillary tube. This pressure change affects the flow dynamics of the refrigerant.

Specifically, an increase in head pressure raises the driving pressure differential across the capillary tube. As a result, more refrigerant is pushed through the tube due to the greater pressure exerted on the refrigerant, which effectively increases its mass flow rate. The design of the capillary tube, which is a fixed orifice, allows for this higher pressure to translate into increased flow when the head pressure rises.

In summary, when head pressure increases, the greater pressure differential causes more refrigerant to flow through the capillary tube, making the correct answer the increase in refrigerant flow through the system. This understanding is important for maintaining proper refrigerant management and system efficiency.