How to distinguish between high-pressure and low-pressure pipes in car air conditioning?
2 Answers
Differentiation methods include observing the thickness of the pipes and comparing temperatures. Below is relevant information on air conditioning maintenance: 1. Heat exchanger: Clean the surfaces of indoor and outdoor heat exchangers to improve their efficiency. When cleaning the indoor heat exchanger, carefully remove the panel and use a soft cloth to wipe it down. Gently brush the heat exchanger of the indoor unit with a small brush to remove dust and harmful accumulations that can breed bacteria. Note that since the fins are made of thin aluminum material, they can easily deform under pressure, so clean them carefully. 2. Filter screen: Remove accumulated dust from the filter screen. When cleaning the filter screen, first turn off the power, then open the air intake grille; remove the filter screen and clean it with water or a vacuum cleaner. The water temperature should not exceed 40 degrees Celsius. Use a hot damp cloth or neutral detergent to clean the filter screen, then dry it with a dry cloth. Do not use insecticides or other chemical detergents to clean the filter screen.
I worked at an auto repair shop for several years, and distinguishing between the high-pressure and low-pressure lines of a car's AC system is crucial. The high-pressure line connects the compressor outlet to the condenser. It's hot to the touch because it carries high-temperature, high-pressure refrigerant, with pressures exceeding 20 bar. These lines are typically thinner to reduce flow resistance and are located near the radiator in the front of the engine bay, sometimes labeled with an 'H' or in red. The low-pressure line runs from the evaporator back to the compressor inlet. It's cool to the touch, with lower pressures of just 2-5 bar, and is thicker to facilitate refrigerant circulation, usually located near the cabin. Be extra cautious when working on these: after turning off the engine, wait for the system to cool down, wear gloves to check temperatures, or use a pressure gauge—red indicates high pressure, blue low pressure. I've seen cases where incorrect connections caused lines to burst, leading to refrigerant leaks that not only damage the car but are also hazardous. Always double-check before servicing, and make it a habit to refer to the manual diagrams to avoid trouble.
