AR20242 | Gymatic 3/B Unloader Valve 3650 PSI Adjustable Pressure

Overview

The AR20242 is a bolt-on Gymatic 3/B unloader valve from Annovi Reverberi,
designed to provide safe pressure regulation and internal bypass for AR high-pressure pumps in the
XM, XMV, XMA, XR, RK, RKA, RKV, RR, RRA, and RRV families. Rated to
3,650 PSI and up to 5.5 GPM, this compact unloader protects the pump
and downstream components by diverting flow whenever the spray gun closes or system pressure reaches
the setpoint. :contentReference[oaicite:0]{index=0}

With a 1/2″ FPT inlet, 3/8″ MPT outlet, and a built-in brass
bypass channel, the AR20242 eliminates the need for external bypass hoses and extra fittings. That
makes it a clean, reliable solution for commercial pressure washers, industrial wash skids, and
OEM pump packages where space, simplicity, and longevity matter. :contentReference[oaicite:1]{index=1}

How the AR20242 Works

Trapped-Pressure Unloader with Internal Bypass

• Functions as a trapped-pressure regulating unloader: when the trigger gun is open,
  water flows straight through to the hose and nozzle; when the gun closes, the valve shifts and
  routes flow through an internal bypass channel back toward the pump inlet. :contentReference[oaicite:2]{index=2}
• Prevents dangerous over-pressurization by releasing excess pressure in the pump head instead of
  allowing pressure to spike against a closed gun or blocked nozzle.
• Internal bypass design eliminates external bypass hoses, reducing leak points and
  simplifying plumbing on compact frames and skid units. :contentReference[oaicite:3]{index=3}

Adjustable Pressure Control

• A molded plastic adjustment knob lets you set operating pressure up to
  the valve’s 3,650 PSI rating, matching the pump/nozzle duty point for your application. :contentReference[oaicite:4]{index=4}
• Once set, the AR20242 maintains consistent working pressure, improving cleaning results and
  reducing unnecessary stress on the pump and accessories.
• Regulated bypass operation helps reduce heat buildup, cavitation risk, and seal wear during
  frequent on/off spraying cycles.

Key Features & Construction

OEM Brass Body with Built-In Bypass

• Brass body for strength and corrosion resistance in high-pressure water and
  detergent environments. :contentReference[oaicite:5]{index=5}
• Built-in bypass channel (brass/aluminum assembly) returns water internally,
  reducing plumbing complexity and making the assembly more compact. :contentReference[oaicite:6]{index=6}
• Stainless-steel plunger and spring components provide reliable sealing and long service life
  under repeated pressure cycling. :contentReference[oaicite:7]{index=7}
• Approximate weight around 2.5 lb, light enough for gun- or frame-mounted use
  without stressing fittings. :contentReference[oaicite:8]{index=8}

Direct-Mount Design for AR Pumps

• Bolt-on unloader designed to mount directly to compatible AR pump heads using
  supplied “banjo” inlet and outlet bolts and washers. :contentReference[oaicite:9]{index=9}
• Fits a wide range of AR pump families, including SXMA, SXMV, XM, XMA, XMV, XR, RK, RKA,
  RKV, RR, RRA, and RRV series — check pump model for confirmation. :contentReference[oaicite:10]{index=10}
• OEM geometry ensures correct alignment and flow paths, helping maintain pump performance and
  reducing installation time versus universal unloaders.

Specifications

Technical Ratings

• Model: AR20242 – Gymatic 3/B bolt-on unloader valve (no injector) :contentReference[oaicite:11]{index=11}
• Maximum Pressure: 3,650 PSI (rated working pressure) :contentReference[oaicite:12]{index=12}
• Flow Range: 3.0 – 5.5 GPM (max 5.5 GPM) :contentReference[oaicite:13]{index=13}
• Inlet Port: 1/2″ FPT (female pipe thread) :contentReference[oaicite:14]{index=14}
• Outlet Port: 3/8″ MPT (male pipe thread) :contentReference[oaicite:15]{index=15}
• Bypass: Internal, brass/aluminum bypass—no external bypass hose required :contentReference[oaicite:16]{index=16}
• Material: Brass body, stainless internal plunger/spring, molded plastic adjustment knob :contentReference[oaicite:17]{index=17}
• Max Fluid Temperature: approx. 165 °F (per spec listings) :contentReference[oaicite:18]{index=18}
• Country of Origin: Italy :contentReference[oaicite:19]{index=19}

Recommended Applications

Commercial & Industrial Systems

• Commercial pressure washers: Ideal for contractor-grade cold-water units and
  mid-size hot-water machines built around AR XM, RK, or RR series pumps.
• Fleet & equipment washing: Protects pumps used to clean trucks, heavy equipment,
  refuse vehicles, and rental fleets where operators frequently cycle the trigger gun.
• Industrial wash skids: Perfect for stationary or trailer-mounted rigs in factories,
  warehouses, and maintenance shops.
• OEM and custom builds: Skid builders and OEMs can standardize on AR20242 for
  compatible AR pump frames to simplify design and service.

Where AR20242 Makes a Difference

• Systems with frequent start/stop cycles, where safe bypass and smooth pressure
  transitions are essential to seal and valve life.
• Rigs where space is limited and eliminating external bypass plumbing helps reduce
  clutter and leak points.
• Applications that demand repeatable, stable operating pressure to protect sensitive
  surfaces or maintain consistent cleaning performance.

Installation & Best Practices

Setup Tips

• Mount the AR20242 directly onto the pump using the correct inlet and outlet bolts; torque to
  the manufacturer’s specifications to prevent leaks or distortion. :contentReference[oaicite:20]{index=20}
• Plumb inlet and discharge with hoses and fittings rated to at least 3,650 PSI and the pump’s
  maximum flow and temperature.
• After installation, set system pressure by adjusting the knob while monitoring
  a pressure gauge at the pump outlet or gun; lock in your working pressure once dialed in.
• Periodically inspect for leaks, sluggish bypass response, or pressure drift—these can signal
  worn seals or debris in the unloader that should be addressed with an OEM repair kit. :contentReference[oaicite:21]{index=21}

Summary

The AR20242 Gymatic 3/B unloader valve is a compact, OEM-engineered solution for
pressure regulation and bypass on a wide range of Annovi Reverberi pumps. Its 3,650 PSI / 5.5 GPM
rating, internal brass bypass, and direct-mount design make it a go-to choice for commercial washers,
industrial skids, and OEM builds that prioritize reliability, clean plumbing, and long pump life.
If you need a robust, no-injector unloader that’s purpose-built for AR XM, RK, RR and related pump
families, AR20242 delivers the control and protection your system depends on.