What is the phenomenon of the expansion valve is broken, and what are the faults of the expansion va

The liquid supply is small, and the refrigerant flow rate provided is small (ice blockage, dirty blockage, and temperature sensor package damage) The liquid supply is large, resulting in liquid return.

The valve plate is stuck) The liquid supply is large and small, and the expansion valve is not selected correctly.

The expansion valve is an important component in the refrigeration system and is generally installed between the reservoir and the evaporator. The expansion valve is composed of three parts: the valve body, the temperature sensing bag, and the balance pipe.

1 composition. To put it simply, the expansion valve is composed of three parts: the valve body, the temperature sensing bag, and the balance pipe.

Temperature bag. The temperature sensing package is filled with refrigerant in a saturated state of gas-liquid equilibrium, which is not compatible with the refrigerant in the system. It is generally tied to the evaporator outlet pipe, and the pipe is in close contact to feel the superheated vapor temperature at the evaporator outlet, because the refrigerant inside it is saturated, so the pressure of the saturated state at the temperature is transmitted to the valve body according to the temperature.

Balance tube. One end of the balance tube is connected to the valve body through a capillary tube at the outlet of the evaporator slightly away from the temperature sensing bag. The function is to transfer the actual pressure of the evaporator outlet to the valve body.

There are two diaphragms in the valve body, and the diaphragm moves upwards under pressure to reduce the flow of refrigerant through the expansion valve, seeking balance in the dynamics.

Quality judgment. The ideal working state of the expansion valve should be to change the opening in real time and control the flow rate as the load of the evaporator changes. However, in reality, due to the hysteresis in the heat transfer of the temperature felt by the thermophore, the reaction of the expansion valve is always half a beat slower.

If we draw a diagram of the time flow of an expansion valve, we will see that it is not a smooth curve, but a wavy line. The quality of the expansion valve is reflected in the amplitude of the twists and turns, the larger the amplitude, the slower the response of the valve, and the worse the quality.

2 functions. It mainly plays the role of throttling and depressurizing and regulating the flow rate.

At the same time, it also has the function of preventing wet compression and liquid shock, protecting the compressor and abnormal overheating.

Manifestation of a broken expansion valve in cold storage.

1.Poor refrigeration: When the expansion valve fails, the refrigeration effect is affected and the temperature inside the air conditioning system becomes unstable. The cold storage cannot reach the set temperature, resulting in the stored items being vulnerable to damage.

2.Temperature instability: When there is a problem with the expansion valve, the flow of refrigerant can be unstable, causing the temperature in the cold room to rise or fall rapidly, unable to reach a stable temperature as needed.

3.Abnormal pressure: When the expansion valve fails, the flow of refrigerant will be restricted, making the pressure during the working process of the compressor abnormal, resulting in the failure of the entire refrigeration system to work normally.

1. This will affect refrigeration, and it will freeze, resulting in improper valve adjustment, affecting high and low pressure, resulting in no air conditioning air;

2. It will also cause the low-pressure pipe to not ice the hand, the drying bottle to frost, the condenser to frost, the expansion valve or the condenser can not hear the swishing sound, the high pressure and low pressure are abnormal, the temperature of the high-pressure pipe is abnormal, etc.;

3. If this happens, the reservoir can still work normally, there is no need to replace the expansion valve, if not, then it needs to be replaced.

The expansion valve plays a throttling role in the air conditioning system. When the system is working, the refrigerant flow rate and system pressure are adjusted by controlling the opening of the expansion valve, so that the system can work normally.

If the expansion valve is dirty, the system will not be able to increase the refrigerant flow even if the expansion valve is opened to the maximum, and the pressure difference between the front and back valves will be too large. The system will have poor refrigeration effect, frost formation behind the valve, and so on.

What is the phenomenon of a broken expansion valve?

The main phenomena of broken expansion valves are as follows.

1.The liquid supply is small, and the refrigerant flow rate provided is small (ice blockage, dirty blockage, and temperature sensor package damage)2The liquid supply is large, resulting in liquid return. (The valve plate is stuck).

Phenomenon: Liquid enters the compressor; low superheat; Inspiratory pressure is normal or slightly elevated.

When the compressor starts, the refrigerant flow is high.

Phenomenon: Liquid enters the compressor; No overheating; The inspiratory pressure is higher than normal.

3.The liquid supply fluctuates from large to small, and the expansion valve is incorrectly selected.

The refrigeration system oscillates, or is intermittently unstable.

Phenomenon: fluctuation of inspiratory pressure; fluctuating inspiratory superheat; The expansion valve sometimes has insufficient liquid supply, and sometimes too much liquid supply.

The simplest phenomenon, if the temperature at both ends of the expansion valve is blocked, one side will freeze, and the other side will not be as simple as that.

Hello, the low-pressure tube does not ice hands, the drying bottle is frosted, the condenser is frosted, the expansion valve or the condenser can not hear the swishing sound, the high pressure and low pressure are abnormal, and the temperature of the high-pressure pipe is abnormal.

Attached: Judgment method:

1. At a temperature of 30 degrees, the pressure on the low-pressure side is about 40ps within 10 minutes after starting the air conditioner, and it is normal for the high-pressure side to be around the right.

2. At a temperature of 30 degrees, 10 minutes after starting the air conditioner, the pressure on the low-voltage side is 40ps, and the pressure on the high-pressure side is above, which is a problem of poor heat dissipation.

3. When the temperature is 30 degrees, after starting the air conditioning system for 10 minutes, the pressure on the low-pressure side is 25ps to 32ps, and the pressure on the high-pressure side is the most normal state. Increasing the throttle appropriately and the pressure on the low side can drop to 22ps.

4. At a temperature of 30 degrees, the air conditioner has been started for a long time, the pressure on the high-pressure side has not been reached, the pressure on the low-pressure side is about 40ps, and the air-conditioning system has added the calibrated refrigerant but the liquid window is still bubbling. At the same time, there is water on the compressor casing on the low-pressure side of the compressor. Expansion valve body failure.

5. At a temperature of 30 degrees, the air conditioner has been started for a long time, the pressure on the high-pressure side has not been reached, and the pressure on the low-pressure side is about 50ps, and the air-conditioning system is filled with calibrated refrigerant but the liquid window is still bubbling. At the same time, there is water on the compressor casing on the low-pressure side of the compressor. The expansion valve body and compressor failed at the same time.

6. At a temperature of 30 degrees, start the air conditioner for a long time, the pressure on the low-voltage side is below 30ps, the pressure on the high-pressure side is in, increase the pressure on the low-pressure side of the throttle to quickly reach about 20ps and do not rise, and the air-conditioning system feels that the coldness is not enough. After the flame is turned off, the pressure on the low-pressure side rises to the fullest. Expansion valve body failure.

7. At a temperature of 30 degrees, add 300 grams of refrigerant, and the pressure on the low-pressure side under the idle bar is less than 10ps, and the micro throttle will become 0ps or a negative value. Don't add any more refrigerant, the expansion valve body fails.

The expansion valve is an important component in the air conditioning system, and its main function is to regulate the flow of refrigerant in the refrigeration system to stabilize the outlet pressure of the condenser in the middle of the evaporator, and then maintain the saturation pressure value of the refrigerant in the condenser. When an expansion valve fails, it can have varying degrees of impact on the entire refrigeration system.

Among them, one of the most obvious phenomena is that the failure of the expansion valve will lead to the instability of the refrigerant flow in the air conditioning system, so that the pressure value changes, and then the temperature of the refrigerant will also drop or rise, resulting in insufficient air conditioning or heating, and it is difficult to maintain proper temperature control due to hail. In addition, a broken expansion valve will also affect the heating effect of the system, resulting in a situation where the temperature does not rise or rises slowly.

In addition, when the expansion valve is damaged, when the refrigeration system is working, there will be an abnormal sound in the air conditioning room, because the inside of the expansion valve is deformed by the action of thermal expansion and cold contraction, which in turn affects the air circulation and emits abnormal noise.

In summary, when the expansion valve fails, the most prominent phenomenon caused by it is that the cooling effect is significantly reduced or cannot have the initial cooling effect at all, and the heating effect will also be affected, and it will also be accompanied by the appearance of abnormal noise, which indicates that the expansion valve must be repaired or replaced to ensure the normal operation of the air conditioning system. <>

The low-pressure pipe does not freeze, the drying bottle is frosted, the condenser is frosted, the expansion valve or condenser cannot hear the swishing sound, the high-pressure and low-pressure pipes are abnormal, and the temperature of the high-pressure pipe is abnormal. The expansion valve plays a throttling role in the air conditioning system. When the system is working, the refrigerant flow and system pressure can be adjusted by controlling the opening of the expansion valve to make the system work normally.

Dirty blockage of the expansion valve can cause the system to fail to increase the refrigerant flow even if the expansion valve is opened to its maximum, and the pressure difference between the front and back of the valve is too large. In the system, there will be poor refrigeration effect, frost formation behind the valve, etc. What will happen if the expansion valve is broken?

1.The amount of liquid ** is small, and the refrigerant flow rate provided is small (ice blockage, dirty blockage, temperature ball damage). 2.

The amount of liquid ** is large, resulting in liquid. Phenomenon: Liquid enters the compressor Yuan Huiye; Low overheating; Inhalation pressure is normal or slightly elevated.

When the compressor starts, the refrigerant flow is high. Phenomenon: Liquid enters the compressor; No overheating; The inspiratory pressure is higher than normal.

3.The size of the liquid supply and the expansion valve are not selected correctly. The system oscillates or is unstable intermittently.

Phenomenon: fluctuation of inhalation pressure; inhalation overheating fluctuations; Expansion valves are sometimes underfed and sometimes oversupplied. Millions of car purchase subsidies.

Here's how to tell if the expansion valve is bad:The broken expansion valve of the automobile air conditioner is manifested as: the low-pressure pipe does not freeze, the dry and grinding is resistant to bottle frosting, the condenser is frosted, the expansion valve or condenser cannot hear the whooshing sound, the high pressure and low pressure are abnormal, and the temperature of the high-pressure pipe is abnormal.

The expansion valve is composed of a valve body, a temperature ball and a balance tube.

It can be determined whether the above phenomenon has occurred.

Expansion valve repair method:1. Change the filter drier.

For dirty blockage, if it is not very serious, it is enough to change a filter drier; If it is very severe, it is necessary to reclean the impurities in the system piping, evacuate and recharge the refrigerant.

2. Apply a hot towel to the ice blockage.

If the degree of ice blockage is serious and has affected the normal operation of the system, the water in the system pipeline should be cleaned up, vacuumed, and refilled with refrigerant.

Faults include:1. There is no sound when the expansion valve is working.

2.The low-pressure pipes of the air conditioning system disappear at low temperatures. 3.

The condenser of the vehicle was frosty. All of the above problems are caused by damage to the expansion valve. The expansion valve of a motor vehicle will become dirty after a period of use, resulting in clogging, and should be cleaned in time.

Automotive expansion valves are an important part of refrigeration systems. It is a sultry high-temperature and high-pressure liquid refrigeration bending agent installed between the reservoir and the evaporator. By throttling into low-temperature and low-pressure steam, the refrigerant absorbs heat in the evaporator to achieve the refrigeration effect.

The expansion valve controls the flow of the valve by changing the superheat at the end of the evaporator, preventing underutilization and height jumping.