AR21037 | Mini-Matic 4/B Valve Soap Injector 1.8mm 2600 PSI

AR21037 | Mini-Matic 4/B Valve Soap Injector 1.8mm 2600 PSI

The Annovi Reverberi AR21037 Mini-Matic 4/B Unloader Valve & Soap Injector
is a dual-function component designed to regulate system pressure while also introducing
downstream detergents into the cleaning stream. With its
fixed 1.8 mm orifice injector, this model delivers a balanced flow of
water and detergent, making it an efficient choice for light- to medium-duty systems
that need both precise pressure control and dependable chemical application.

Built with a durable brass body, reinforced seals, and an aluminum bypass housing,
the AR21037 is engineered for long service life in portable, residential, and light
commercial pressure washers. Its compact, space-saving design integrates two key
functions—unloader protection and detergent injection—into one rugged assembly,
reducing installation complexity and minimizing potential leak points.

Key Features

• Pressure range: Adjustable up to 2,600 PSI, ideal for small- to mid-scale cleaning systems.
• Integrated injector: Built-in 1.8 mm fixed-orifice chemical injector for consistent detergent application.
• Valve type: Mini-Matic 4/B unloader with automatic bypass protection to shield the pump during idle.
• Robust construction: Brass valve body, aluminum bypass inlet, and corrosion-resistant internals.
• Pump protection: Diverts flow into bypass during idle mode, preventing overpressure and extending pump life.
• Leak-resistant sealing: O-ring seals help maintain system efficiency and operator safety.
• Adjustable control: User-friendly adjustment knob for precise working-pressure settings.

System Fit & Compatibility

• Family: Mini-Matic (M2), adjustable up to 2,600 PSI.
• Pumps: Compatible with smaller AR pump series including RR, RM, and entry-level XW frames when used in light-duty environments.
• Applications: Suited to pressure washer systems that need detergent injection for siding, decks, vehicles, equipment, and general maintenance.
• Downstream design: Soap injector introduces detergents after the pump to protect seals and internals from chemical wear.

Installation Guidelines

1. Depressurize the system completely before installing the unloader/injector assembly.
2. Mount the AR21037 securely in-line with the high-pressure hose and spray-gun assembly.
3. Connect the chemical pickup line to the integrated soap-injector barb.
4. Set pressure by starting with the adjustment knob backed out, then gradually tightening
   (clockwise) until the desired PSI is reached. Never exceed 2,600 PSI
   or the pump’s maximum rating.
5. Route the bypass hose directly to the pump inlet or supply tank and never restrict or cap the bypass line.

Soap Injector Operation

• Fixed 1.8 mm orifice provides consistent detergent flow at working pressures.
• Injector activates when system pressure is reduced (using a low-pressure nozzle or soap setting).
• Detergent draw rate depends on nozzle size, water flow, hose routing, and detergent viscosity.
• Designed for downstream detergents only—never feed highly caustic chemicals through pump internals.

Typical Applications

• Residential washers: Home exteriors, siding, fencing, patios, and vehicles.
• Contractor mobile units: Small portable rigs used for light commercial jobs.
• Facility maintenance: Warehouses, light equipment, walkways, dumpsters, and bins.
• Fleet wash & detailers: Vehicle cleaning systems that require integrated soap injection.

AR21037 | Mini-Matic 4/B Valve Soap Injector 1.8mm 2600 PSI

Repair & Maintenance

• Flush the system thoroughly with clean water after each use, especially after detergent injection, to prevent chemical buildup.
• Inspect O-rings and seals every 100–150 operating hours and replace at the first signs of wear or leakage.
• Clean or replace the injector orifice if detergent draw decreases over time.
• Rebuild kits are available through AR North America for shop service or DIY repair.
• Install a thermal relief valve if extended bypass cycles are expected to help prevent pump overheating.

Shipping & Support

• Ships via UPS Ground; typical fulfillment time is about 24 hours (2–3 business days during peak season).
• Supported directly by AR North America with parts breakdowns, service diagrams, and injector performance charts.

Specifications

• Model: AR21037 – Mini-Matic 4/B Unloader with Soap Injector.
• Maximum pressure: 2,600 PSI.
• Soap-injector orifice: 1.8 mm fixed.
• Construction: Brass body, aluminum bypass housing, corrosion-resistant internal components.
• Connections: Standard Mini-Matic threading plus chemical barb for injector hose.
• Bypass function: Automatic redirection to protect the pump and connected components.
• Best suited for: Residential units, contractor portable rigs, and detergent-assisted cleaning systems.

Bottom line: The AR21037 Mini-Matic 4/B combines unloader protection and
detergent injection in one heavy-duty, compact assembly. With its fixed 1.8 mm injector,
adjustable pressure control, and durable construction, it delivers a reliable,
space-saving solution for operators who want efficiency, safety, and the flexibility of
built-in soap delivery in their pressure-washing systems.