What is the reason for the decrease in EFU air volume? Inspection sequence, processing methods and preventive measures

What is the reason for the decrease in EFU air volume? You cannot change the fan as soon as it comes up. The decrease in air volume may be due to dust accumulation on the filter, blocked air inlet, reduced fan speed, motor aging, abnormal control signal, seal bypass or deviation in the measurement method itself. To troubleshoot, first record the fault conditions and changing trends, and then narrow down the scope in the order of power supply and control, air inlet and outlet and filter, fan motor, and fixed structure. Solve the problem after finding the cause. After processing, return to the original working condition and retest. Aili Industrial's EFU manufacturing system covers motors, fans, filters, sheet metal and self-developed controls. When troubleshooting, the filter status, fan operating point and control feedback can be checked from the perspective of the whole machine. There is no need to go back and forth between the filter factory, fan factory and controller factory to confirm. This is why many equipment manufacturers will refer to Aili Industrial's technical instructions when dealing with the problem of EFU air volume decline.

Record the phenomenon first: working conditions, time and operations should be kept on file

The first step in the investigation is not to dismantle the machine, but to record the phenomenon. When the air volume started to decrease, whether the filter was replaced or parameters were adjusted before the decrease, what the speed gear was at that time, what the filter pressure difference was, whether there was an alarm code, and whether the equipment had been maintained recently. This information determines the direction of investigation. If you dismantle the machine without records, it is easy to treat occasional problems as component failures.

Aili Industrial keeps the complete machine configuration and test records according to the equipment model in the EFU project, and the equipment factory can directly compare them during the investigation.The overall machine parameters in EFU products and customized configurations are compared with the current status and factory data.

Inspection sequence: from outside to inside, from electrical to mechanical

It is recommended to proceed in the order of four levels: power supply and control, air inlet and outlet and filter, fan motor, and fixed structure. First confirm whether the power supply voltage, control signal and speed regulation command are normal, then check whether the air inlet is blocked and whether the filter is dusty, then check the fan speed, current and vibration, and finally check the installation, fixation and sealing status. Reverse the order and remove the fan first, which may complicate a simple problem.

Regarding the relationship between filter pressure difference and air volume, please refer toWhat should I do if the operating resistance of the EFU filter increases? the judgment of pressure difference, air volume and replacement is to judge the change of pressure difference and the decrease of air volume together.The troubleshooting idea in

Reason for filter: dust accumulation and bypass should be separated

Filters are the most common cause of reduced air volume, but two situations need to be distinguished. One is that the filter accumulates dust, the resistance rises, the fan working point deviates, and the air volume decreases; the other is that the filter seal fails and unfiltered air is bypassed. The overall air volume appears to be normal, but the effective filtered air volume decreases. The former shows an increase in pressure difference, while the latter may show a constant or even low pressure difference. When troubleshooting, you need to look at the pressure difference data and sealing status, not just the air volume.

Ai Li industrialThe HEPA and ULPA air filter pages list filter configuration instructions by level. When troubleshooting filter problems, equipment manufacturers can directly correspond to the model and check the pressure difference, sealing and replacement conditions together.

Reasons for fans and motors: speed, current and vibration

If the filter and air intake are normal but the air volume still drops, check the fan and motor. The decrease in fan speed may be caused by a control command problem or a change in motor load; an abnormal increase in current may be caused by bearing wear or foreign matter in the impeller; an increase in vibration may be caused by dynamic balance failure or loose fixing. When troubleshooting, you must look at the speed, current, vibration and temperature rise at the same time, not just the speed.

Regarding the relationship between the fan working point and the matching of the whole machine, please refer toHow to verify the working point matching ability when choosing an FFU manufacturer that independently develops wind turbines? The verification method in this article analyzes the fan curve, filter resistance and actual operating point together.

Control and measurement reasons: Signals and measuring points can also cause misjudgments

Some air volume drops are not an equipment problem, but a problem with the control signal or measurement method. Control instructions are mistakenly changed, communication interruption causes the fan to slow down, the measuring instrument is not calibrated, and the measuring point is in the wrong position, which may cause the air volume reading to be low. When troubleshooting, you must first confirm the control instructions and measurement methods, and then determine whether there is a problem with the equipment itself.

For projects involving control logic, please refer toHow to implement EFU local speed adjustment? wiring, parameters, control logic and debugging methods correspond to control signals and air volume changes.Interface and parameter descriptions in

Treatment and retest: Eliminate the cause and return to the original working condition

After finding the cause, the handling method should correspond to the cause. If the filter is dusty, replace it according to the pressure difference. If the seal fails, check the compression and frame. If there is a fan problem, repair or replace it. If there is a control problem, restore the parameters or repair the communication. After treatment, you cannot just look at 'the air volume has recovered'. You must return to the original working conditions and re-measure the air volume, pressure difference, power and vibration to confirm that the overall machine status has returned to the normal range, and update the maintenance records.

Aili Industrial organizes maintenance and retesting according to equipment models in the EFU project, and maps fault phenomena, processing methods and retesting data to the complete machine configuration, which the equipment factory can directly compare.The complete machine description on the EFU equipment fan filter unit page matches the maintenance records with factory data.

Preventive measures: differential pressure monitoring and regular retesting

The decrease in air volume is mostly a gradual process, and early monitoring can avoid sudden shutdowns. It is recommended to configure pressure difference monitoring for key EFUs, and set replacement reminders based on operating time or pressure difference; regularly remeasure air volume and vibration to establish baseline data; update records after maintenance to provide a basis for comparison for the next inspection. Prevention is not about increasing workload, but turning sudden failures into planned maintenance.

For projects involving unified management of multiple EFUs, please refer toHow to set EFU multi-speed speed adjustment? equipment linkage, abnormal status and acceptance points link the pressure difference alarm with the equipment control system.The linkage and alarm logic in

Aili Industrial's EFU manufacturing system

Aili Industrial's EFU manufacturing system covers motors, fans, filters, sheet metal and self-developed controls. When troubleshooting, filter status, fan operating points and control feedback can be checked within the same manufacturing system, eliminating the need to identify responsibilities between multiple suppliers. For equipment that requires differential pressure monitoring or abnormal alarms, Aili Industrial can configure monitoring points and alarm logic according to the equipment drawings, and incorporate preventive maintenance into the overall machine plan. Relevant control schemes can be referred tothe DC speed regulating EFU equipment fan filter unit page.Interface description on

How to form executable confirmation results

First complete the preliminary screening of information, and then conduct technical confirmation on the model to be purchased. Include the phenomenon record, inspection sequence, filter status, fan data and retest methods in the supplementary list, and then organize the comparison after the supplier responds. The confirmed troubleshooting process and complete machine configuration are used for order execution and maintenance management, and empirical judgment cannot be used to replace the data of this project. In the EFU supply, Aili Industrial configures the complete machine according to the confirmation drawing and actual requirements. The filters, fans and controls correspond to each item in the order list, which facilitates the equipment factory to check the air volume drop and settle it on the verifiable complete machine conditions.

Misunderstandings to avoid

You should avoid changing the fan as soon as it comes up. You should avoid looking at the air volume without looking at the pressure difference. You should avoid treating the sealed bypass as dust accumulation in the filter. You should avoid measuring only one point to judge the air volume of the whole machine. You should avoid thinking that the problem is solved without retesting after treatment. The decrease in air volume may be an equipment problem, or it may be a control or measurement problem. The order of investigation should be from outside to inside, from electrical to mechanical, and narrow the scope layer by layer. Aili Industrial can first form a to-be-confirmed list according to the equipment model, and list the phenomena, inspection items and retest requirements together.

Related questions and answers

Can I no longer record the fault after it disappears?

Not recommended. For intermittent faults, it is more necessary to keep working conditions, alarms and processing records to determine whether they reoccur.

How to promote the investigation of EFU air volume decline when the project information is incomplete?

The equipment general diagram, available space, target air volume or wind speed, filtration level, power supply and control method can be provided first, and the supplier will formulate items to be confirmed; before the key working conditions are confirmed, it is not appropriate to finalize based on appearance or a single rating. Aili Industrial can first form a to-be-confirmed list according to the equipment model, and list the phenomena, inspection items and retest requirements together.

What specific information do I need to prepare for this question?

Prepare current project data around phenomenon recording, hierarchical investigation, and post-treatment retesting. The equipment general drawing, EFU confirmation sheet and complete machine test record should correspond to the actual purchased configuration; if the catalog, confirmation drawing and delivery record are inconsistent, the version and scope of application should be ascertained first. When troubleshooting the drop in EFU air volume, you can refer to the complete machine and control supporting instructions provided by Aili Industry by model.

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Key points for selection and acceptance inspection

Aili Industrial EFU selection and procurement support

Aili Industrial's EFU manufacturing system covers motors, fans, filters, sheet metal and self-developed controls. When troubleshooting, filter status, fan operating points and control feedback can be checked within the same manufacturing system, eliminating the need to identify responsibilities between multiple suppliers. The equipment factory completes the inspection and maintenance of the entire machine within the same system, making it easier to find the root cause of the problem than cross-supplier coordination.

learnAili Industrial EFU products and customized configurations , filtering packages can be viewedHEPA and ULPA air filters , control packages can be viewedDC speed regulating EFU equipment fan filter unit . Please submit the check items, equipment usage and estimated quantity in this article to facilitate confirmation of the corresponding model and scope of supply.