1. Product Overview
The OSWNKW-76 pre-filter is designed to protect your household water supply system from secondary pollution. It effectively filters out solid impurities such as rust, sediment, algae, and colloids from pipelines. This initial filtration step helps prevent water pollution, pipeline corrosion, and extends the lifespan of household appliances like water purifiers, dishwashers, coffee machines, water heaters, washing machines, underfloor heating systems, and faucets.
The 10-inch model is specifically designed to be installed with the included 316 stainless steel mesh filter cartridge; other filter cartridges are not compatible.
Figure 1: The OSWNKW-76 pre-filter as the first level of water filtration.
2. Specifications
| Parameter | Detail |
|---|---|
| Product Name | Pre filter |
| Model Number | OSWNKW-76 (available in 6-inch and 10-inch variants) |
| Shell Material | 304 Stainless Steel (main unit die-cast, cup body 1.2mm thick) |
| Filter Element Material | 316L SUS Stainless Steel Mesh |
| Filtering Accuracy | 40 μM |
| Working Pressure | 0.1-0.4 MPa (29-58 PSI) |
| Applicable Water Temperature | 0-100 °C |
| Water Flow Rate | 6-inch model: 6000 L/H 10-inch model: 10000 L/H |
| Dimensions (6-inch model) | 285mm (height) x 157mm (overall width) |
| Dimensions (10-inch model) | 375mm (height) x 157mm (overall width) |
| Interface Diameter | DN20 (3/4"), also compatible with 1/2", 1" MNPT fittings |
| Installation Type | Vertical |
| Power Source | Non-electric |
| Purifying Position | Central Purification |
| Use | Household Pre-Filtration |
| Certification | RoHS |
Figure 2: Product Specification Parameters.
Figure 3: Dimensions of the 6-inch model.
3. Package Contents
The OSWNKW-76 Pre-Filter package includes the following items:
- 1 x OSWNKW Pre-Filter Unit
- 1 x User Manual (this document)
- 2 x G1/2" MNPT Fittings or G3/4" MNPT Fittings or G1" MNPT Fittings (depending on selected variant)
- 1 x Drain Ball Valve
- 1 x Water Pressure Gauge
- Washers (quantity may vary)
Note: Threaded adapters for specific pipe types (e.g., copper, PEX, CVC) are not included and must be purchased separately according to your installation needs.
Figure 4: List of Accessories.
4. Installation
4.1 General Placement
The pre-filter should be installed after the main water meter and main water valve, and before household appliances that use water. It is recommended to install it approximately 35cm from the ground.
Figure 5: Typical installation diagram showing placement before household appliances.
Figure 6: Whole house application diagram.
4.2 Installation Steps and Precautions
- Before beginning installation, ensure all components are present and in normal condition.
- Wrap raw material tape (Teflon tape) fully and evenly around the inlet and outlet threads of the filter to ensure a watertight seal.
- When tightening the thread of the filter bottle with a wrench, ensure it is securely tightened but not overtightened to prevent damage.
- After installation, carefully inspect all connecting parts for any leakage or seepage.
- The pre-filter comes with a plug cover for one-time transportation. This plug cover is prohibited from use during installation.
- It is recommended to install a pressure reducing valve before the pre-filter if your working water pressure is outside the 0.1-0.4MPa range. Adjust the pressure reducing valve to the appropriate water pressure to avoid damage to the water purifier and other appliances.
Figure 7: Compact size allows for under-sink installation.
Figure 8: Exploded view of the filter components.
5. Operation
5.1 Water Pressure Monitoring
The built-in water pressure gauge allows for real-time monitoring of your water pressure. The general household water pressure range is 0.1MPa-0.4MPa (29PSI-58PSI). Monitor this to ensure optimal performance and to identify any abnormal pressure situations promptly.
5.2 Flushing
Flushing the pre-filter is a quick and simple process that does not require tools. To flush, simply rotate the drain ball valve 90 degrees downwards. This will allow accumulated sediment to be flushed out. Ensure the sewage outlet is connected to a sewage pipe or a suitable container before flushing.
If the filter screen accumulates viscous impurities or particles that cannot be removed by normal flushing, it may affect the outlet pressure. In such cases, the filter screen can be disassembled for thorough cleaning (see Maintenance section).
6. Maintenance
6.1 Filter Cartridge Cleaning
The filter cartridge should be cleaned every 15-30 days, or when you notice a significant drop in water pressure or visible accumulation of sediment.
- To access the filter cartridge, open the clips securing the filter housing.
- Carefully remove the filter cartridge.
- Clean the filter cartridge thoroughly under running water, brushing off any accumulated sediment.
- Once clean, reinstall the filter cartridge and secure the clips.
The filter's clamp design allows for one-click disassembly, making maintenance convenient and fast.
Video 1: Demonstration of filter disassembly and reassembly for cleaning.
Figure 9: Twisting the filter element for removal.
Figure 10: Clamp-type structure for easy disassembly.
7. Troubleshooting
7.1 Low Water Pressure
- Clogged Filter Screen: If the filter screen is heavily saturated with sediment, it can restrict water flow and reduce pressure. Perform a thorough cleaning of the filter cartridge as described in the Maintenance section.
- High Water Pressure: If the water pressure is consistently too high (above 0.4MPa or 58 PSI), it can cause issues. Consider installing a pressure reducing valve before the pre-filter and adjust it to the recommended operating pressure range of 0.1-0.4MPa.
7.2 Leakage or Seepage
- Improper Thread Sealing: Ensure that raw material tape (Teflon tape) is fully and evenly wound around all threaded connections. Reapply if necessary.
- Loose Connections: Check all connections and ensure they are securely tightened.
7.3 Unstable Water Pressure
- If you are going out for a long time or if water pressure is unstable at night, it is advisable to close the main water inlet gate of the pre-filter tap water to prevent potential issues.
8. User Tips
- Filter Replacement: While the 316L stainless steel mesh filter is designed for repeated cleaning, if it becomes damaged or excessively worn, replacement may be necessary. Contact the manufacturer or seller for compatible replacement filters.
- TDS Value: Note that this pre-filter is designed for sediment removal and does not change the Total Dissolved Solids (TDS) value of the water. The filtered water will retain its natural minerals.
- Long Absences: If leaving your home for an extended period, it is recommended to close the main water inlet valve to the pre-filter.
9. Warranty and Support
For warranty information, technical support, or to inquire about replacement parts, please refer to the official OSWNKW website or contact your authorized dealer. Keep your purchase receipt as proof of purchase.
A user manual in PDF format is available for download from the product page or by contacting customer support. (Reference: User manual (PDF))