Air Conditioning (A/C) & Heating Certification Practice Test – Prep & Study Guide

In orifice tube systems, the liquid line from the condenser outlet to the evaporator inlet is expected to be warm, not cool. This is because the refrigerant in the liquid line has not yet entered the evaporator and is still under pressure after being condensed in the condenser. Cooling occurs as the refrigerant absorbs heat inside the evaporator; therefore, it is crucial for the liquid line to remain at a warmer temperature as it carries the high-pressure refrigerant to the evaporator.

In contrast, the other statements accurately reflect the characteristics of proper orifice tube system operation. The suction line should indeed feel cool to touch, which indicates that the refrigerant has evaporated and is absorbing heat from the surroundings as it flows from the evaporator to the compressor. The evaporator should feel cold, as it is designed to absorb heat from the air surrounding it, thus providing cooling. The accumulator, which collects any excess refrigerant and prevents liquid from reaching the compressor, should be cool to the touch, revealing that it is effectively separating vapor and liquid phases of refrigerant.