Accumulators are very important in hydraulic systems. They store energy and control pressure. When they malfunction, the system often becomes unstable. This article will explain common hydraulic accumulator failure symptoms based on observable phenomena, what these symptoms typically indicate, how to determine if the problem lies with the accumulator, and what steps to take after confirming the issue, helping you make more informed decisions.
What Are the Common Hydraulic Accumulator Failure Symptoms?
When diagnosing hydraulic accumulator failure symptoms, you don’t need to take the equipment apart and inspect it straight away. Instead, just watch how the equipment works. Many problems will be directly reflected in the system pressure, pump operating status, and actuator movements. Here are some typical symptoms that are most easily seen in the field.
Pressure-related Symptoms
When the equipment stops, the pressure drops quickly.
When the system is maintaining pressure, the pressure will continuously decrease and will not remain at the set level.
When starting up or running, it takes longer for the pressure to rise to the set value.
Pump-related Symptoms
The hydraulic pump keeps starting and stopping, and it won’t stop completely.
Even on a light load, the pump runs often.
Actuator-related Symptoms
The movement of the hydraulic cylinder or motor is sometimes fast and sometimes slow.
There is a noticeable shock when the equipment starts or reverses direction.
Noise and Vibration Symptoms
The pipes vibrate a lot when they are working.
The system makes noticeable impact sounds or irregular noises when it is switched on.
These problems don’t necessarily indicate which specific part is damaged, but if multiple issues occur at the same time in the same system, it usually means that the part of the system responsible for storing energy or regulating is no longer working properly and should be investigated further.
What Do These Symptoms Usually Indicate?
When these things happen in a system, it’s usually not because one part has failed, but because of a few common problems. When we look at how the system is working, these patterns show that some of the functions that should be there are getting weaker or even disappearing.
Loss of Stored Energy
Normally, the accumulator releases energy when it’s needed to help keep the pressure in the system. When this ability gets worse, the first sign is that pressure can’t be kept up: as soon as the equipment stops, the pressure drops quickly. To keep the pressure up, the hydraulic pump has to start often to refill the pressure. Even when the equipment doesn’t need a lot of power, the pump is almost always on. The system seems busy but is not working efficiently.
Reduced Damping Effect
If your hydraulic system is working properly, you should be able to change the pressure smoothly, and the system should be quiet. When the damping effect weakens, pressure changes are directly transmitted to the pipelines and components. Common symptoms include: pipe vibration, impact noises during startup, shutdown, or load changes, and generally noisier operation.
Unstable System Response
If the system responds normally, the actions of the actuators are usually continuous and controllable. When the response becomes unstable, the actions become unpredictable: sometimes there’s a slight delay in starting, sometimes there’s a sudden acceleration, and the impact during direction changes becomes more obvious. Operators often feel that the equipment is not working well. Even if the settings haven’t changed, the operating status changes between good and bad.
Increased Load on Other Components
If the accumulator stops working, the tasks it was supposed to perform are transferred to other components, most commonly the hydraulic pump. You will notice that the pump runs for longer, gets hotter, and makes more noise. This uses more energy for the whole system. This is usually not a problem with the pump itself, but rather because it is being forced to do more than it was designed to do.
These failure modes do not show exactly where the damage is, but they do show that the system’s energy storage and buffering functions are not working normally. We can then look into it more to see if the problem is related to the accumulator.
How Can You Confirm Whether the Accumulator Is the Real Problem?
When solving problems, the real challenge is often not finding the problem itself, but working out whether the symptoms you see are caused by the accumulator. The following three steps outline the most common and simple way to check for this problem.
Check for Changes in System Behavior
Many problems with accumulators do not show as an unusual pressure reading, but rather as a change in how the system is working. The most obvious sign is that the pressure drops more easily, and the pump starts to refill the pressure more often. If the system becomes busier and struggles to maintain stable pressure, even though the load and operating conditions haven’t changed, there may be a problem with the accumulator.
Observe System Response When the Accumulator Is Isolated
If you think there’s a problem with the accumulator, you can first reduce how much it’s doing in the system and then see how the system responds. If there are big changes in system shocks, fluctuations, or pump operation, it indicates that the problem is highly related to the accumulator; if the system shows little or no reaction, then it’s likely not an accumulator problem.
Use Precharge Condition as a Final Check
Whatever you saw at the start, we need to check the pre-charge status to make sure the accumulator can work properly. There are usually only two possible results: if the pre-charge is much too low, the accumulator will not be able to store energy, and the system will naturally be unstable; if the pre-charge is normal, the problem is probably not with the accumulator itself, but rather with the system circuit or other components. This step is important because it lets you tell for sure whether the problem is with the accumulator, instead of just guessing based on feeling.
What Happens If Accumulator Failure Symptoms Are Ignored?
When an accumulator malfunctions, it rarely causes the equipment to break down straight away. More often, the system carries on working, but in a slightly different way. If you keep ignoring these changes, the problem will gradually spread from the accumulator to other components.
Impact on Pumps and Motors
If the accumulator doesn’t store energy properly, the system relies solely on the hydraulic pump to maintain the required pressure. At first, you might only notice the pump starting more often than before. After a while, you’ll notice it hardly ever stops completely. The hydraulic pump switches between pressurising, stopping, and pressurising again, causing the motor temperature to gradually rise and the noise to become louder. So, hydraulic pumps often fail not because they’re poor quality, but because they’re doing the work that the accumulator was designed for. This puts too much strain on the pump and can cause it to fail.
Impact on Valves and Seals
When the accumulator’s buffering effect weakens, pressure changes in the system become more direct. Pressure changes that should have been absorbed are now going straight to the valves. You might not notice this straight away, but you will over time: the hydraulic valves will not operate as smoothly, shifting will feel harsher, and the noise will become sharper. The same is true for the seals. They don’t fail all at once, but they gradually wear down from repeated pressure surges, which leads to leaks.
Impact on System Stability and Process Quality
For the people using the equipment, the most obvious sign that something is wrong is that the equipment is not running smoothly. Sometimes the movements are normal, but sometimes they are slow. It is hard to control the pressure holding time, and the rhythm of the movements is not consistent. When you make or test equipment, this change will be directly reflected in the results. Sometimes the results are normal, but sometimes they’re not as good as expected. For example, the equipment doesn’t clamp properly, and it doesn’t stay stable when it should. This makes the test results unreliable.
These effects usually don’t appear suddenly, but build up over time while the system is still working. If they start to affect how stable the process is or how safe the operation is, the problem is often not just with the accumulator itself, but with the whole system.
What Should You Do After Identifying Accumulator-Related Symptoms?
Once you’ve confirmed that these problems are related to the accumulator, you don’t have to immediately take it apart or replace it. Instead, you should look at the situation in detail before deciding what to do next. Here are some of the most common approaches seen in the field.
If Precharge Is Low but Stable
If the pressure is low but steady, it usually means that the accumulator is working, but not in the right range. In this case, you need to restore the pressure to its normal level and then check if the system performance becomes stable. Many systems show a big improvement after this step.
If Precharge Cannot Be Maintained
If the pressure can’t be kept up after the adjustment and it drops again soon after, it’s probably an internal problem, not just a problem with the adjustment. You need to think about whether the bladder, diaphragm, or related seals have broken. It’s useless to keep waiting to deal with this issue. We need to concentrate on the internal parts of the accumulator.
If precharge Is Normal but Symptoms Remain
If the pre-charge state is normal but the system keeps failing, you need to focus your attention on something else. At this point, it would be better to check the pump’s pressure control method, the valve’s operation, and the system’s overall working principle, instead of focusing on the accumulator.
If Similar Issues Repeat across Systems
If you keep having the same problems on different devices or with the same system, and it doesn’t get better even after replacing the accumulator, then the problem is probably not with just one part. It’s more likely to be something to do with how the parts are chosen or how the system is set up. In this case, we need to go back to the design stage. We need to check if the accumulator capacity, pre-charge setting, and its role in the system are right.
What Information Helps Speed Up Troubleshooting or Replacement Decisions?
When talking to suppliers, it’s often better to have key information ready than to give a long explanation. The following information will help you to decide quickly whether to replace a part, no matter what your role is. If you prepare it in advance, it will also help you to make decisions more quickly.
System Pressure Range
The highest and lowest pressures the system can reach.
This is the approximate pressure level during normal use.
This information helps others to understand how the accumulator works.
Accumulator Type and Size
What type is it – bladder, diaphragm, or piston?
How much space does it have, and what is the basic model?
These factors determine how the accumulator works and are important for deciding if it is suitable.
Installation Location and Main Function
Where is the accumulator installed? Is it at the pump outlet, near the valve block, or on the actuator side?
What is it used for? Is it for pressure maintenance, shock absorption, or emergency power supply?
The application for the same type of accumulator is different, so the way you solve the problem will also be different.
Observed Symptoms
The pressure drops quickly.
The pump keeps switching on and off.
The operation is unstable, or there are noticeable shocks/vibrations.
Please describe what you see, hear and feel on site, but don’t make any judgements.
Checks Already Done
Have you noticed any changes in the pressure?
Have you done any tests to see if there are any differences?
Have you checked the status before charging?
This information can stop you from wasting time trying to solve the same problems over and over again, and help the other person quickly find the main issues.
The more information you give them, the easier it will be for them to identify the problem, the faster they can make decisions, and there will be a lower possibility of incorrect part replacements or repeated troubleshooting.
Safety Considerations Before Testing or Servicing an Accumulator
Before doing any testing or maintenance, safety must always be the top priority. Accumulators are devices that store energy. They can still be under pressure even when the system is shut down. Before inspecting or handling an accumulator, make sure that all the pressure has been released. Don’t assume the pressure has gone away. Any work on accumulators should be done according to the equipment’s instructions and the on-site safety rules.
FAQ
Can an accumulator look like it is not leaking but still not be working properly?
Yes, it’s possible. Sometimes the insides of an accumulator stop working, and even if it looks fine on the outside, it may no longer be able to store energy properly.
Could the problem with the accumulator be connected to how long the system has been in use?
Yes, there is a link. If you use it more often, the insides of the accumulator get older, and it probably won’t work as well.
If a system has more than one accumulator, how can I tell which one is causing the problem?
You can solve the problems one by one and see which accumulator has the biggest effect on the system. The problem is often with that particular accumulator.
Could a broken accumulator actually be dangerous to the system?
Yes, there is a risk in certain situations, especially when the accumulator is used to absorb shocks or maintain pressure.
If the system is still working, can we just leave the accumulator problem for now?
It might work for a short time, but in the long run, it will make other parts of the system work harder and cause problems.
Do different types of accumulators show very different symptoms when they fail?
There are differences, but at the system level, the symptoms are often similar. The main differences are in how they respond and how they fail.
Final Thoughts
This article talks about common symptoms of accumulators and how to think about them to figure out what’s causing them, which will help you make better decisions. Target Hydraulics has been making accumulators and hydraulic units for over 10 years. We can help you choose the right product, give advice on how to use it, and provide replacement solutions. If you need help with any problems related to accumulators, please contact us.
