Product
Flygt FML-35 / FS-M-L35 35 mm Lower Mechanical Seal for 3126, 3127, 4440 & 5530
| Place of Origin | China |
| Brand | Hong Teng |
| Marketing Reference | FML-35 |
| Seal Reference | FS-M-L35 |
| Nominal Size | 35 mm |
| Seal Position | Lower Mechanical Seal |
| Compatible Equipment | Selected Flygt 3126, 3127, 4440 and 5530 equipment |
| Product Type | Aftermarket replacement mechanical seal |
| Ordering Check | Confirm complete model suffix, lower seal position, old seal and critical dimensions before ordering. |
Product Details
The FML-35 / FS-M-L35 is a 35 mm lower mechanical seal supplied as an aftermarket replacement for selected Flygt equipment. It is intended for maintenance and overhaul applications where the existing lower seal configuration matches the FS-M-L35 reference.
Product Specifications
- Product Name: Flygt FML-35 / FS-M-L35 35 mm Lower Mechanical Seal
- Marketing Reference: FML-35
- Seal Code / Reference: FS-M-L35
- Nominal Size: 35 mm
- Installation Position: Lower mechanical seal
- Brand: Hong Teng
- Place of Origin: China
- Product Type: Aftermarket replacement mechanical seal
- Application: Maintenance and overhaul of selected compatible Flygt equipment
Flygt Compatibility Reference
| Flygt Model | Lower Seal | Upper Seal Reference |
|---|---|---|
| 3126.091 / 3126.280 / 3126.290 | FS-M-L35 | FS-K-U35 |
| 3126.181 | FS-M-L35 | FS-M-U35 |
| Selected 3127 variants | FS-M-L35 | FS-M-U35 |
| Selected 4440 applications | FS-M-L35 | FS-M-U35 |
| Selected 5530 variants | FS-M-L35 | FS-M-U35 |
Flygt 3126.090 and 3126.180 are commonly cross-referenced with the FS-K-L35 lower seal rather than FS-M-L35. Do not select FML-35 only because the pump belongs to the 3126 family or uses a 35 mm seal size.
Confirm the complete Flygt model and numerical suffix, lower seal position, old seal appearance and dimensions. For 3127, 4440 and 5530 equipment, provide the full nameplate reference whenever available.
Product Description
The FML-35 mechanical seal, also identified by the reference FS-M-L35, is a 35 mm lower mechanical seal for selected Flygt equipment. It is intended for maintenance, overhaul and seal replacement where the installed lower sealing component matches this reference.
Correct identification is especially important on Flygt 3126 equipment. The base model number “3126” does not identify one universal 35 mm lower seal. Common replacement cross-references distinguish between different numerical suffixes. For example, 3126.091, 3126.280, 3126.290 and 3126.181 can be associated with FS-M-L35, while 3126.090 and 3126.180 commonly use a different lower seal reference.
If your pump is 3126.090 or 3126.180, see our Flygt FKL-35 / FS-K-L35 lower mechanical seal before selecting this product. Separating these references helps avoid ordering a seal based only on the 35 mm nominal size.
When the old seal reference is unknown, dimensional verification should be used together with the full equipment nameplate. Record the shaft or sleeve diameter, seal working dimensions, stationary and rotating components and installation position. See our mechanical seal measurement guide for the dimensions commonly required for replacement identification.
For other upper, lower and cartridge seal references, browse our Flygt replacement mechanical seals and identify the seal from the complete pump or mixer model whenever possible.
Flygt names, trademarks and model numbers are used only to identify compatible applications. This FML-35 / FS-M-L35 product is an independently manufactured aftermarket replacement supplied by Hong Teng and is not represented as an original Flygt product.
Application
Applications
The FML-35 / FS-M-L35 35 mm lower mechanical seal is intended for maintenance and replacement work on selected Flygt equipment using a compatible separate upper-and-lower mechanical seal arrangement.
- Flygt 3126.091
- Flygt 3126.181
- Flygt 3126.280
- Flygt 3126.290
- Selected Flygt 3127 variants
- Selected Flygt 4440 applications
- Selected Flygt 5530 variants
- Wastewater, sewage and slurry equipment maintenance
- Mechanical seal replacement and equipment overhaul
Important Notice
Do not identify this seal only from the 35 mm size or the base model 3126. Flygt equipment can use different upper and lower seal combinations depending on the numerical suffix and configuration. In particular, 3126.090 and 3126.180 should not automatically be treated as FS-M-L35 applications.
How to Confirm an FML-35 / FS-M-L35 Replacement
Use the following checks together before ordering. The full equipment model, seal position and old seal should take priority over appearance alone.
Record the Complete Model
Photograph the equipment nameplate and record the complete Flygt model. On a 3126 unit, distinguish between suffixes such as 3126.090, 3126.091, 3126.181, 3126.280 and 3126.290 rather than providing only “3126.”
Confirm the Lower Seal Position
FS-M-L35 refers to the lower mechanical seal. Do not confuse it with an upper seal such as FS-M-U35 or FS-K-U35. If possible, photograph both seals before disassembly so their installed positions remain clear.
Check the Old Seal & Dimensions
Confirm the nominal 35 mm size together with the complete rotating and stationary components, critical diameters and installation dimensions. Similar-looking Flygt seals can use different mounting arrangements.
Verify the Seal Pairing & Materials
Check which upper seal is paired with the lower seal and confirm the existing face and elastomer materials where possible. Material suitability should also be evaluated against the pumped medium and operating conditions.
3126 Variant Check
| Model Reference | Common Lower Seal Reference | Selection |
|---|---|---|
| 3126.090 / 3126.180 | FS-K-L35 | Check FKL-35 instead |
| 3126.091 / 3126.280 / 3126.290 | FS-M-L35 | FML-35 reference |
| 3126.181 | FS-M-L35 | FML-35 reference |
Original Flygt Sealing-System Reference
Xylem technical information describes selected Flygt equipment as using double-seal systems with separate mechanical seals and distinguishes inner and outer sealing positions. The referenced Flygt product range includes the 3126, 3127, 4440 and 5530 model families.
This official information is useful for understanding the original Flygt sealing-system concept. It does not identify the Hong Teng FS-M-L35 aftermarket reference and should not be interpreted as a guaranteed rating or exact replacement specification for this product.
Frequently Asked Questions
Common questions about identifying the FML-35 / FS-M-L35 lower mechanical seal.
What is the FML-35 mechanical seal?
FML-35 is Hong Teng’s marketing reference for the FS-M-L35 35 mm lower mechanical seal. It is supplied as an aftermarket replacement for selected Flygt equipment where the existing lower seal configuration matches this reference.
Which Flygt models use the FS-M-L35 lower seal?
Common replacement references include Flygt 3126.091, 3126.181, 3126.280, 3126.290 and selected 3127, 4440 and 5530 equipment. Always confirm the complete model and old lower seal before ordering.
Does every Flygt 3126 use the FML-35 lower seal?
No. Different 3126 variants can use different lower seals. For example, 3126.090 and 3126.180 are commonly associated with FS-K-L35, while 3126.091, 3126.181, 3126.280 and 3126.290 can use FS-M-L35.
Is FS-M-L35 an upper or lower mechanical seal?
FS-M-L35 is the lower seal reference. The upper mechanical seal may use a different reference depending on the Flygt model and variant, so the installation position should be confirmed before ordering.
Can I order the seal using only the 35 mm size?
No. The 35 mm nominal size is only one identification parameter. The complete Flygt model, numerical suffix, lower seal position, old seal design and critical dimensions should also be checked.
What information should I send for replacement confirmation?
Please provide the complete Flygt nameplate reference, clear photos of the upper and lower seals, the old lower seal after removal, available dimensions and material information. This allows compatibility to be checked before shipment.
Is this an original Flygt mechanical seal?
No. This is an independently manufactured aftermarket replacement mechanical seal supplied by Hong Teng. Flygt trademarks and model references are used only for compatibility identification.








Company Profile
Dongguan Hongteng Seals Co., Ltd. Company was established in 1996. The company has passed the GB/T19001-2016 idt ISO9001:2015 quality management system certification. The company has world-renowned pump mechanical seals, axe mechanical seals, fluid mechanical seals, metal bellows mechanical seals, container mechanical seals, rubber bellows mechanical seals, O-ring seals, PTFE mechanical seals, stainless steel oil seals, skeleton oil seals, hydraulic oil seals, automotive water seals and various mechanical seal materials, hard alloys, silicon carbide, carbon graphite, alumina, etc. There are Guangzhou Port, Shenzhen Port, and Foshan Port in the surrounding area, with developed and efficient logistics. The company has a stock warehouse of over 2000 square meters, which can efficiently and quickly deliver goods.

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frequently asked questions
01. Q: Are you a factory or a trader?
A: We are a production factory and also sell on our own
02. Q: Where is your factory located?
A: Our factory is located in Dongguan City, and the nearest ports are Guangzhou Port and Shenzhen Port. Other ports can also be selected according to customer needs
03. Q: What is your delivery time in days?
A: For products in stock, we can ship immediately when receive the payment; For other projects, we need 10-25 days for mass production
04. Q: Do you provide free samples?
A: We usually do not provide free samples, and the sample fee can be deducted after the second order
05. Question: What is the most commonly used mode of transportation
A: The weight and size of mechanical seals are relatively small, and air freight, sea freight, and express delivery are usually the preferred transportation methods for customers.
06. Q:What payment methods do you accept?
A: For products in stock, 100% advance payment is required and immediate shipment will be made upon receipt of payment. For customized products, a 30% advance payment and a 70% payment must be made before the order is shipped. We accept T/T, Western Union, and also welcome customers to make payments through Alibaba
07. Q: Can you provide me with customized production
A: Yes, we can customize products and welcome OEM









