MTM Hydro BRV31/90 High-Flow Black-Spring Unloader – 4,060 PSI 24-GPM

The MTM Hydro BRV31/90 is a high-flow trapped-pressure unloader designed for pressure washing and industrial cleaning systems producing up to 24 GPM. When the spray gun or discharge valve closes, the unloader diverts pump flow through the bypass circuit to control system pressure and protect compatible equipment.

This black-spring model is rated for up to 4,060 PSI and 194°F and uses large 1/2" BSP female ports for high-flow plumbing. Multiple inlet and bypass ports provide flexibility when configuring multi-pump pressure washers, hydro-excavation systems, sewer-jetting equipment, and other high-output cleaning systems.

Key Features:

• High 24 GPM flow capacity
• Black main spring identifies the 4,060 PSI configuration
• Trapped-pressure operation diverts pump flow into bypass when the discharge closes
• Dual inlet and bypass ports support flexible plumbing orientation
• Large 1/2" BSP ports accommodate high-flow applications
• Stainless-steel shaft provides resistance to rust and adjustment forces
• Guided main spring promotes stable alignment
• Brass construction
• Designed and manufactured in Italy
  

Specifications:

• Manufacturer: MTM Hydro
• Model: BRV31/90
• Part Number: 18.0412
• Unloader Type: High-flow trapped-pressure unloader
• Maximum Pressure: 4,060 PSI
• Maximum Flow: 24 GPM
• Maximum Temperature: 194°F / 90°C
• Inlet Ports: Two 1/2" BSP female
• Outlet Port: One 1/2" BSP female
• Bypass Ports: Two 1/2" BSP female
• Available Bottom Mounting Port: 1/2" BSP female
• Body Material: Brass
• Shaft Material: Stainless steel
• Main Spring Color: Black
• Country of Manufacture: Italy
  

Additional Information:

• This unloader uses BSP threads, not NPT. NPT fittings should not be forced into BSP ports.
• Match the unloader to the pump system’s actual flow and pressure.
• Use the correctly sized spray nozzle to establish normal operating pressure. Do not use the unloader as the primary method of reducing cleaning pressure.
• Incorrect adjustment or restricted bypass plumbing can damage equipment or create an unsafe overpressure condition.
  
• Confirm the port locations, available space, and plumbing arrangement before replacing another unloader model.
• Unloader only; pressure gauge, hoses, fittings, and mounting hardware are not included.