Hydraulic Solenoid Valves: Common Faults and Solutions

hydraulic solenoid valve
Figure 1: Hydraulic solenoid valve.

A hydraulic solenoid valve is one of the commonly used control components in hydraulic systems, and its working reliability directly affects the normal operation of the system. In order to ensure the stability and safety of the hydraulic system, if a hydraulic solenoid valve fails, it needs to be troubleshot or repaired in time.

Failures of hydraulic solenoid valves can be divided into two categories: mechanical failures and electrical failures. Mechanical faults include seal failure, solenoid valve stuck, valve core wear, etc. Electrical faults include line faults, poor switch contact, solenoid coil disconnection and burnt out, etc. When troubleshooting a hydraulic solenoid valve fault, you should first determine the fault type and then repair it according to the corresponding solutions.

The following summarizes the common faults, causes and solutions of hydraulic solenoid valves. When the solenoid valve you use has such faults, you can troubleshoot them one by one according to these causes.

1. Common Fault Causes and Troubleshooting Methods of Hydraulic Solenoid Valves

1.1 Hydraulic Solenoid Valve Does Not Work When Energized

1. It may be caused by poor power supply wiring;
2. The power supply voltage is not within the working range;
3. The wiring connection between the valve coil and the power supply is desoldered;
4. There is a short circuit in the coil;
5. The working pressure difference of the solenoid valve does not meet the needs of the system;
6. The solenoid valve used does not meet the equipment requirements, causing the fluid temperature to be too high;
7. There are impurities in the valve, causing the valve core to become stuck;
8. The viscosity of the liquid being transported is too high, and the service life of the valve has expired.

1. Reconnect the junction box connector;
2. Adjust the power supply voltage to the normal range;
3. Re-weld;
4. Replace the coil with a new one;
5. Adjust the working pressure difference or replace the solenoid valve;
6. Replace the solenoid valve with one appropriate;
7. Clean the valve. If the seal is damaged, it should be replaced and a filter should be installed;
8. Replace the solenoid valve.

hydraulic solenoid valve core
Figure 2: Valve core.

1.2 Hydraulic Solenoid Valve Stuck

1. Hydraulic system contamination: The accumulation of contaminants in the hydraulic system can cause the valve core in the solenoid valve to become stuck.
2. The solenoid valve core is stuck: the front or rear end of the valve core is stuck due to damage or wear.
3. Solenoid coil failure: short circuit, open circuit or poor contact in the circuit.

1. Clean the hydraulic system: Use professional cleaning fluid to clean the entire hydraulic system to remove accumulated contaminants.
2. Replace the solenoid valve core and the relevant parts.
3. Replace the solenoid coil: Check whether the circuit is normal, and replace the solenoid coil if necessary.

Methods to prevent solenoid valve from getting stuck:
1. Keep the hydraulic system clean: Regularly clean the hydraulic system to prevent the accumulation of contaminants.
2. Take effective maintenance measures: Regularly check the status of the solenoid valve and replace parts that need to be replaced.
3. Choose a high-quality solenoid valve supplier to ensure that the solenoid valves used are of reliable quality, fundamentally avoiding problems such as jamming caused by product defects.

hydraulic solenoid valve solenoid coils and valve cores
Figure 3: Hydraulic solenoid valve parts.

1.3 Hydraulic Solenoid Valve Acts Slowly

1. There is dirt inside the solenoid valve or the parts are aging;
2. The oil quality of the hydraulic system is poor or the oil passage is blocked;
3. The low ambient temperature causes the oil viscosity to become high and the solenoid valve to respond slowly;
4. The power supply voltage of the solenoid valve coil is unstable or the coil itself is damaged.

1. Remove the dirt inside the solenoid valve or replace aging parts;
2. Regularly replace the oil inside the hydraulic system and ensure that the oil passage is smooth;
3. Increase the ambient temperature, or use low-temperature hydraulic oil;
4. Check whether the solenoid valve power supply voltage is stable. If the voltage is unstable, check the circuit.
5. Using a solenoid valve with a feedback circuit can detect the feedback signal to control the opening and closing of the solenoid valve in time to avoid delayed action.

dirt on a hydraulic solenoid valve
Figure 4: Dirt on a solenoid valve.

1.4 Hydraulic Solenoid Valve Makes Too Much Noise

Noise is one of the important sources of pollution in hydraulic systems. It is very harmful, not only affecting the service life of the equipment, but also reducing the efficiency of the system.

Causes and solutions:
1. Inappropriate working environment conditions
The working environment of the solenoid valve is relatively complex, involving ambient temperature, ambient humidity, medium temperature, medium properties, working pressure, etc. If it cannot meet the standards, it will cause instability of the solenoid valve during operation, faster wear and damage of parts, and excessive noise during work.

To solve the problem, you need to replace the solenoid valve with one that is suitable for the current environment.

2. Parts damage, such as spring aging
After long-term use, the internal parts of solenoid valves will inevitably be worn and damaged, resulting in unstable working conditions and greater noise.

If the parts have aged and can no longer be used, replace them with new ones.

3. Too low voltage
Too low voltage will also cause the product to work abnormally and cause noise.

Solving this problem is very simple. Just increase the voltage.

4. Too high system pressure
Excessive system pressure causes the solenoid valve to be unable to work within its adapted working range, resulting in poor operation stability and noise.

To solve this problem, you need to adjust the system pressure to the range that the solenoid valve is suitable for.

5. Impurities on the valve core
During the operation of the solenoid valve, external impurities (such as dust, oil, debris, etc.) may enter the system. They may cause the valve to work unstable and cause noise during operation.

The solution is to clean the valve regularly to remove impurities.

6. Lack of lubrication
During long-term operation of the solenoid valve, its parts will rub against each other. If there is a lack of sufficient lubrication, physical friction will also cause loud noises.

Therefore, during the operation of the solenoid valve, the internal lubrication of the parts needs to be checked regularly. If the lubricating oil is insufficient, it needs to be added.

hydraulic power unit including an electric motor, solenoid valve set, etc
Figure 5: Hydraulic power unit.

1.5 Hydraulic Solenoid Valve Leaking Oil

The causes of this failure may be poor sealing, aging, valve body wear, valve core wear, etc.

1. Clean or replace seals, valve body and valve core
If oil leakage from the hydraulic solenoid valve is caused by aging seals, they need to be replaced. You need to pay attention to the model and specifications of the seals to ensure the correct replacement.

2. Check the installation of hydraulic solenoid valve
If installed incorrectly, the hydraulic solenoid valve may not be sealed tightly, causing oil leakage. Therefore, check if the installation is correct and make adjustments.

3. Replace the hydraulic solenoid valve
If neither of the above solutions solves the problem, the entire hydraulic solenoid valve may need to be replaced. When replacing, you need to pay attention to the model and specifications of the old hydraulic solenoid valve to ensure that the new one being installed is correct.

4. Maintain hydraulic solenoid valve
Hydraulic solenoid valves require regular care and maintenance during the working process to keep good working condition. Regular cleaning and inspection can effectively prevent them from leaking oil.

5. Ask professionals to handle it
If you do not have relevant knowledge and professional skills about hydraulic solenoid valves, or handle it improperly, it will bring risk to yourself. Therefore, it is recommended to ask professional hydraulic engineers or technicians to handle it.

replace the old solenoid valve with a new one
Figure 6: Replace a solenoid valve.

2. Conclusion

In the process of repairing the hydraulic solenoid valve, the operating procedures should be strictly followed to avoid blindness. When you meet a solenoid valve fault, analyze the cause first, and then the corresponding method to solve it. If the problem is minor, you can try to adjust the valve core position, retighten the screws, clean the valve, add lubricating oil, replace seals or the coil, check and repair the circuit, etc. If the situation is more complicated, you need to ask professional repair personnel to repair it.

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