
Brand: | Zurn Wilkins |
Category: | Backflow Prevention, 375 Series |
Size Range: | 20-25mm |
Other Sizes: | |
Connection: | Threaded Male BSPT |
Product Description
The Zurn Wilkins 375 Series Backflow Preventer is a High Hazard, High-Performance, Low Head Loss Backflow Preventer that features a lightweight ductile iron body, offering durability and easy installation. Constructed with corrosion-resistant low-lead materials, as well as all-plastic and stainless-steel components, this backflow preventer guarantees long-lasting reliability, ensuring a secure and efficient water system. This is also AS/NZS listed.




Typical Application
Designed for installation on potable water lines to protect against both back siphonage and backpressure of contaminated water into the potable water supply. Reduced Pressure Zone Device Assembly shall provide protection where a potential health hazard exists. (High Hazard)
Standards Compliance
- Australian Watermark (AS/NZS 2845.1) Certified Lic. 1379

Technical Data
Operating Parameters
Maximum working water pressure: 1200kPa
Maximum working water temperature: 82°C
Hydrostatic test pressure: 2400kPa
Materials
Housing Reinforced: Nylon
Fasteners Stainless: Steel, 300 Series
Elastomers: Silicone, Buna Nitrile
Internals: Delrin, Nylon
Springs: Stainless steel, 300 series
Tailpieces: Cast Bronze, Lead-Free
Struts: Stainless steel, 300 series
End connections: Threaded Male BSPT
Test connections: 1/4" SAE 45° Flare
Flow Characteristics
Model 375 20 & 25mm (STANDARD & METRIC)

Zurn Wilkins - 375LXL20-25mm - Flow characteristics
Relief Valve Discharge Rates

Zurn Wilkins - 375LXL20-25mm - Relief Valve Discharge Rates
Technical Specifications
The Reduced Pressure Principle Backflow Preventer shall be Australian WaterMark Certified (AS/NZS 2845.1), rated to 82°C and supplied male pipe thread tailpieces. The main body shall be Nylon and the seat disc elastomers shall be silicone. The Reduced Pressure Principle Backflow Preventer shall be a Zurn Wilkins Model 375.
Typical Installation
Local codes shall govern installation requirements. To be installed in accordance with the manufacturers’ instructions and the latest edition of the Plumbing Code of Australia and/or AS/NZS 3500. Unless otherwise specified, the assembly shall be mounted at a minimum of 12” (305mm) and a maximum of 30” (762mm) above adequate drains with sufficient side clearance for testing and maintenance. The installation shall be made so that no part of the unit can be submerged.

Zurn Wilkins - 375LXL20-25mm - Typical Installation
Dimensions and Weights


Zurn Wilkins - 375LXL20-25mm - Dimensions and Weights
Zurn Wilkins - 375LXL Series - Backflow Preventer 20-25mm - Device Only

Product Code | Size | Description |
---|---|---|
375LXL020 | 20mm | Zurn Wilkins - Model 375 - 20mm - Threaded Male BSP |
375LXL025 | 25mm | Zurn Wilkins - Model 375 - 25mm - Threaded Male BSP |
375LXL032 | 32mm | Zurn Wilkins - Model 375 - 32mm - Threaded Male BSP |
375LXL040 | 40mm | Zurn Wilkins - Model 375 - 40mm - Threaded Male BSP |
375LXL050 | 50mm | Zurn Wilkins - Model 375 - 50mm - Threaded Male BSP |
Product Code | Size | Description |
---|---|---|
375LXL020+S | 20mm | Zurn Wilkins - Model 375 with Y Strainer - 20mm - Threaded Male / Female BSP |
375LXL025+S | 25mm | Zurn Wilkins - Model 375 with Y strainer - 25mm - Threaded Male / Female BSP |
375LXL032+S | 32mm | Zurn Wilkins - Model 375 with Y strainer - 32mm - Threaded Male / Female BSP |
375LXL040+S | 40mm | Zurn Wilkins - Model 375 with Y strainer - 40mm - Threaded Male / Female BSP |
375LXL050+S | 50mm | Zurn Wilkins - Model 375 with Y strainer - 50mm - Threaded Male / Female BSP |
Product Code | Size | Description |
---|---|---|
375LXL020+SV | 20mm | Zurn Wilkins - Model 375 with Y Strainer & Ball Valves - 20mm - Threaded Female / Female BSP |
375LXL025+SV | 25mm | Zurn Wilkins - Model 375 with Y strainer & Ball Valves - 25mm - Threaded Female / Female BSP |
375LXL032+SV | 32mm | Zurn Wilkins - Model 375 with Y strainer & Ball Valves - 32mm - Threaded Female / Female BSP |
375LXL040+SV | 40mm | Zurn Wilkins - Model 375 with Y strainer & Ball Valves - 40mm - Threaded Female / Female BSP |
375LXL050+SV | 50mm | Zurn Wilkins - Model 375 with Y strainer & Ball Valves - 50mm - Threaded Female / Female BSP |
Additional Accessories

Product Code | Size | Description |
---|---|---|
YSBR015 | 15mm | 20 Mesh Line Strainer Female BSP - 15mm |
YSBR020 | 20mm | 20 Mesh Line Strainer Female BSP - 20mm |
YSBR025 | 25mm | 20 Mesh Line Strainer Female BSP - 25mm |
YSBR032 | 32mm | 20 Mesh Line Strainer Female BSP - 32mm |
YSBR040 | 40mm | 20 Mesh Line Strainer Female BSP - 40mm |
YSBR050 | 50mm | 20 Mesh Line Strainer Female BSP - 50mm |

Product Code | Size | Description |
---|---|---|
015MF | 15mm | Ball Valve - Threaded Male / Female BSP - 15mm |
020MF | 20mm | Ball Valve - Threaded Male / Female BSP - 20mm |
020FF | 20mm | Ball Valve - Threaded Female / Female BSP - 20mm |
025MF | 25mm | Ball Valve - Threaded Male / Female BSP - 25mm |
025FF | 25mm | Ball Valve - Threaded Female / Female BSP - 25mm |
032MF | 32mm | Ball Valve - Threaded Male / Female BSP - 32mm |
032FF | 32mm | Ball Valve - Threaded Female / Female BSP - 32mm |
040MF | 40mm | Ball Valve - Threaded Male / Female BSP - 40mm |
040FF | 40mm | Ball Valve - Threaded Female / Female BSP - 40mm |
050MF | 50mm | Ball Valve - Threaded Male / Female BSP - 50mm |
050FF | 50mm | Ball Valve - Threaded Female / Female BSP - 50mm |
Spare Parts / Repair Kits
Product Code | Size | Description |
---|---|---|
RK34-375 | 20mm | Model 375 - Check/Relief Module Set - Complete Kit |
RK34-375R | 20mm | Model 375 - Check/Relief Module Set - Rubber Only Kit |
RK1-375 | 25mm | Model 375 - Check/Relief Module Set - Complete Kit |
RK1-375R | 25mm | Model 375 - Check/Relief Module Set - Rubber Only Kit |

Pos. | Description | Qty |
---|---|---|
1 | O-Ring - Housing Outlet | 1 |
2 | O-Ring - Sleeve | 1 |
3 | O-Ring - Relief Valve Cover | 1 |
4 | O-Ring -Relief Valve Stem | 1 |
5 | O-Ring - Housing Inlet | 1 |
6 | O - Ring - Relief Valve seat (7) | 1 |
7 | Relief Valve Seat | 1 |
8 | #2 Check Assembly | 1 |
9 | #1 Check Assembly | 1 |
10 | Relief Valve Stem Assembly | 1 |
11 | Lubricant | 1 |
12 | Relief Valve Spring | 1 |

Pos. | Description | Qty |
---|---|---|
1 | O-Ring - Housing Inlet | 1 |
2 | O-Ring - #1 check Valve | 1 |
3 | Diaphragm | 1 |
4 | Check Seal Rings | 2 |
5 | Relief Valve Seal Ring | 1 |
6 | O-Ring Relief Valve Cover | 1 |
7 | O-Ring - Relief Valve Seat | 1 |
8 | O-Ring - Relief Valve Stem | 1 |
9 | O-Ring - Housing Outlet | 1 |
10 | O-Ring - Sleeve | 1 |
11 | O-Ring - #2 Check Valve | 1 |
12 | Lubricant | 1 |

Pos. | Description | Qty |
---|---|---|
1 | #1 Check Assembly | 1 |
2 | #2 Check Assembly | 1 |
3 | Relief Valve Stem Assembly | 1 |
4 | O-Ring - Sleeve | 1 |
5 | O-Ring - Housing Inlet | 1 |
6 | O-Ring Housing Outelt | 1 |
7 | O-Ring - Relief Valve Seat(10) | 1 |
8 | O-Ring - Relief Valve Stem | 1 |
9 | O-Ring - Relief valve cover | 1 |
10 | Relief Valve Seat | 1 |
11 | Relief Valve Spring | 1 |

Pos. | Description | Qty |
---|---|---|
1 | O-Ring - Housing Inlet | 1 |
2 | O-Ring - #1 Check Seat | 1 |
3 | O-Ring - #2 Check Seat | 1 |
4 | O-Ring - Housing Outlet | 1 |
5 | O-Ring - Sleeve | 1 |
6 | O-Ring - Relief Valve Seat | 1 |
7 | O-Ring - Relief Valve Stem | 1 |
8 | O-Ring - Relief Valve Cover | 1 |
9 | Check Seal Rings | 2 |
10 | Relief valve seal Ring | 1 |
11 | Diaphragm | 1 |