How to distinguish between the low-pressure pipe and high-pressure pipe of a car air conditioner?
2 Answers
To distinguish between the high-pressure and low-pressure pipes in a car air conditioner, observe the thickness of the pipes and compare their temperatures. Generally, the thicker pipe is the low-pressure pipe, which feels cool to the touch during operation. The low-pressure side includes the evaporator, accumulator, return pipe, compressor input side, and compressor oil sump. The thinner pipe is the high-pressure pipe, which feels hot to the touch during operation. The high-pressure side includes the compressor output side, high-pressure pipe, condenser, receiver-drier, and liquid pipe. Here is some additional information about car air conditioners: 1. Definition of a car air conditioner: The car air conditioning system is a device that cools, heats, ventilates, and purifies the air inside the vehicle, providing a comfortable environment for passengers, reducing driver fatigue, and improving driving safety. 2. Application of car air conditioners: Most cars use an integrated heating and cooling air conditioning system. The layout typically combines the evaporator, heater core, centrifugal blower, and control mechanism into a single unit, known as the air conditioner assembly.
I used to think about this issue when driving my old car. I remember one time the air conditioning wasn’t cooling, so I tried to figure out which pipe was faulty. The low-pressure pipe felt extremely cold, like it had just come out of a fridge, and the pipe wall was thinner, usually located on the driver’s side connected to the evaporator. The high-pressure pipe was the opposite—it was so hot it felt like boiling water, and you couldn’t keep your hand on it for long. It was thicker and mostly found in the engine bay near the condenser. Simple summary: the easiest way to tell them apart is by touch—cold is low pressure, hot is high pressure. Also, when the AC is running, the pressure difference between these two pipes causes expansion and contraction changes. The low-pressure system is also prone to frosting, so it’s best to use gloves for safety when checking. In short, once you learn this, you can prevent refrigerant leaks or compressor damage, and you won’t have to worry about the AC failing on the road.
