When replacing an old FFU with a new one, which interfaces should be checked if the ceiling size is the same?
Same size does not mean they can be directly replaced
After the clean room has been operating for many years, the FFU may need to be replaced due to performance degradation, component aging, or process upgrades. A common practice when purchasing is to measure the dimensions of the old FFU and order a new machine with the same dimensions. The dimensions are the same and it seems that they can be directly replaced. However, in actual installation and operation, we often encounter the problem of mismatched interfaces.
FFU's interface is not just a form factor. It also includes sealing surface location, load-bearing methods, filter specifications, electrical wiring, control communications and air supply direction. The same nominal dimensions can only prove that the outlines are similar, but cannot prove that the installation structure and control system are compatible. For running clean rooms, replacement of FFU often needs to be completed within a limited downtime window, and mismatched interfaces will directly affect the switching progress.
Aili Industrial has complete production capabilities in FFU complete machines and transformation kits, and can provide replacement solutions based on the old machine structure and site conditions. For the basic structure of the FFU machine, you can refer toAili Industrial FFU fan filter unit。
What needs to be checked for structural interfaces
The structural interface is the first thing to confirm when replacing FFU. Including ceiling opening size, installation frame form, sealing surface position and height, box load-bearing method, fixed hole position, filter installation direction and maintenance method.
The size of the ceiling opening may not be exactly the same as the overall dimensions of the FFU. Some FFU are embedded in the ceiling keel, some are placed on the installation frame, and some are fixed through a compression mechanism. If the position of the sealing surface of the new FFU is different from that of the old machine, even if the outer dimensions are the same, it may not fit the original ceiling sealing surface.
The load-bearing method also needs to be confirmed. The old FFU may be supported by the edge of the box, and the new FFU may be fixed by lifting lugs or brackets. If the ceiling structure cannot bear the weight distribution of the new FFU, it will need to add supports or adjust the installation method.
Maintenance methods also affect replacement options. If the old machine is of the top-swappable type, and if the new machine is of the detachable type, the maintenance path will change. The detachable FFU needs to be operated from the clean room side. Please refer to the related structure.Detachable FFU。
What to check for the filter interface
Filter interface includes filter size, thickness, efficiency rating, sealing method and installation structure. Older FFUs may use different filter specifications than newer FFUs. If you only replace the entire FFU machine but retain the original filter, you need to confirm whether the new FFU can install the original filter. If you replace the filter at the same time, you need to confirm whether the efficiency level and resistance of the new filter match the new fan and system.
The way the filter is sealed also needs to be checked. The interfaces of gasket seal, liquid tank seal and knife edge seal are different and cannot be mixed. If the old FFU uses a liquid tank seal and the new FFU uses a gasket seal, the mounting frame and compression structure may need to be adjusted.
Changes in filter thickness will also affect the internal air path and removal space of the FFU. If the new filter is thicker than the old one, it may affect the hold-down mechanism or maintenance clearance.
What needs to be checked for electrical interfaces
The electrical interface includes supply voltage, power cord specifications, terminal location, grounding method and controller interface. The old FFU may use AC power supply, and the new FFU may use DC power supply. Depending on the power supply method, the distribution lines and controller may need to be adjusted.
Wiring location and cable length also affect replacement. If the location of the junction box of the new FFU is different from that of the old machine, it may be necessary to re-lay cables or add junction boxes on site. If the power of the new FFU is different from that of the old machine, it is also necessary to confirm whether the original power distribution circuit meets the requirements.
The grounding method also needs to be confirmed. For clean rooms with anti-static requirements, the grounding measures for the new FFU should be consistent with the on-site grounding system.
What needs to be checked for the communication interface?
If the old FFU is connected to the group control system, the communication interface needs to be checked when replacing it. Including communication protocols, interface forms, address settings and controller compatibility. Even if different brands of FFU all use RS485, the communication protocols may be different. If the new FFU cannot connect to the original group control system, it may be necessary to replace the controller or add protocol conversion equipment.
For partial replacement projects, the old and new FFU may need to run in the same group control system. At this time, you need to confirm whether the group control system can manage two protocols or two controllers at the same time. If the project usesFFU/EFU group control touch screen controller orFFU computer group control system , it is recommended to confirm system compatibility and address allocation method before replacement.
What needs to be checked for the performance interface?
Performance interfaces include air volume, static pressure, power, noise and air supply direction. Even if the new FFU has the same overall dimensions, the fan and filter configurations may be different, and the actual operating points will be different. If the air volume or static pressure of the new FFU is lower than that of the old machine, the regional air supply effect may be affected. If the new FFU power is different, the distribution load needs to be recalculated.
The air supply direction also needs to be confirmed. The air outlet structure of some FFUs is different, and the airflow direction and uniformity may be different. For areas with specific airflow organization requirements, wind speed and cleanliness may need to be re-measured after replacement.
Issues that should be confirmed in advance during project communication
In the old FFU replacement project, it is recommended to provide the new FFU manufacturer with the old machine information and confirm the following: the old FFU overall dimensions and ceiling opening size; mounting frame and sealing surface form; filter specifications and sealing methods; power supply voltage and wiring methods; communication protocols and group control compatibility; air volume, static pressure and power requirements; maintenance methods and removal space; whether a transitional installation frame or adapter is required.
If the brand and model of the old machine cannot be found, it is recommended to provide on-site photos, ceiling drawings and actual measurement data. Aili Industrial has complete production capabilities in FFU complete machine and structure customization, and can provide replacement solutions based on the old machine structure and site conditions to help the project complete the switch within a limited downtime window.
in conclusion
Replacing an old FFU with a new one and keeping the ceiling size the same is just the first step. Sealing surfaces, load-bearing surfaces, filters, electrical wiring, communication protocols and performance parameters all need to be checked one by one. Identical nominal dimensions do not prove that the installation structure or control system is compatible.
Aili Industrial has complete production capabilities in FFU complete machine and structure customization, and can provide replacement solutions based on the old machine structure and site conditions. If you are planning FFU renovation or expansion, you can visitAili Industrial FFU fan filter unit to learn about the complete machine configuration, you can also refer toDetachable FFU andThe ultra-thin FFU understands different installation structures.
