RKV4G37D-F24C2I | 4.0 GPM 3700 PSI Triplex Pump Unloader Installed

RKV4G37D-F24C2I by Annovi Reverberi — RK Series Triplex Plunger Pump with Gymatic Unloader and Chemical Injector | 4.0 GPM | 3,700 PSI | Bronze Connecting Rods | 1″ Hollow Keyway Shaft | SAE J609A Gas and Diesel Engine Drive

The RKV4G37D-F24C2I by Annovi Reverberi is a professional-grade RK Series triplex ceramic plunger pump engineered for gas and diesel engine-driven commercial and industrial pressure washing systems requiring high-volume 4.0 GPM output at 3,700 PSI with integrated downstream chemical application capability. Rated at 4.0 GPM and 3,700 PSI at 3,400 RPM, the RKV4G37D-F24C2I delivers 14,800 cleaning units — combining the high-volume coverage speed of 4.0 GPM with 3,700 PSI pressure output that handles heavy contamination, grease, and large commercial surfaces more aggressively than standard 3,000–3,200 PSI platforms — through a reinforced crankcase with bronze connecting rods, solid ceramic plungers, and an F24 SAE J609A direct-drive flange for close-coupling to gasoline or diesel engines without adapters or intermediate couplings.

The RKV4G37D-F24C2I is built on the RK Series platform — AR’s industrial pump architecture with front-access piston packing and valve assemblies for simplified field maintenance. The Gymatic (C2) unloader with integrated downstream chemical injector delivers the complete two-mode wash platform — high-pressure rinse and low-pressure detergent pre-soak — through a single factory-configured assembly that simplifies system design for contractors, OEM rig builders, and equipment wash bay operators.

Built by Annovi Reverberi in Modena, Italy — with US-based operations, a domestic parts distribution network, and dedicated AR North America technical support — the RKV4G37D-F24C2I arrives as a complete, factory-tested assembly. Pre-filled with AR break-in oil, equipped with a Gymatic unloader and active downstream chemical injector, and packaged with mounting bolts and fasteners, a vented dipstick, operator’s manual, and full parts schematic, this pump is ready to install from the moment it arrives. Protected by a 5-year US limited warranty through AR North America and built to be fully rebuilt rather than replaced, the RKV4G37D-F24C2I is a long-term investment in a high-output RK Series commercial pump platform capable of a decade of productive service life.

Decoding the RKV4G37D-F24C2I Model Number

What Every Segment of This AR Pump Designation Tells You

The RKV4G37D-F24C2I encodes pump series, output, shaft type, flange interface, unloader family, and injector configuration directly:

• RKV — Pump series: RK Series triplex plunger pump — AR’s industrial pump platform built around a reinforced crankcase with front-access piston packing and valve serviceability for continuous commercial duty
• 4G37 — Performance rating: 4.0 GPM flow rate at 3,700 PSI maximum operating pressure — 14,800 cleaning units
• D — Shaft version: Direct Gas/Diesel Drive — 1″ hollow keyway crankshaft bore for direct coupling to gasoline or diesel engine 1″ output shafts
• F24 — Flange type: SAE J609A direct-drive flange for RK Series ‘D’ version pumps — close coupling to gas or diesel engines with a 1″ I.D. cylindrical shaft (AR part AR41866)
• C2 — Unloader code: Gymatic (C2 = Gymatic per AR suffix designation) — Gymatic series internal bypass unloader, brass body, adjustable pressure regulation. Verify with AR North America that the C2 Gymatic specification has been validated for this 3,700 PSI operating point.
• I — Chemical injector: Included — a downstream soap and chemical injector is integrated into the Gymatic unloader assembly, enabling low-pressure detergent application without a separate injector fitting

The RKV4G37 Family — Four Variants, One Versatile 3,700 PSI Platform

The RKV 4.0 GPM / 3,700 PSI family includes four configurations sharing the same RK Series platform, reinforced crankcase, bronze connecting rods, and front-access serviceability:

• RKV4G37DF24VR35 — Gymatic VR35, no injector. Straight 3,700 PSI water output. Correct for external chemical management.
• RKV4G37D-F24C2I (this model) — Gymatic (C2) with integrated downstream chemical injector. Two-mode wash capability with Gymatic bypass regulation at 3,700 PSI.
• RKV4G37D-VR35ID — Gymatic VR35 with integrated injector, D variant. Two-mode wash. Originally rated 3,700 PSI, re-rated to 4,000 PSI — serves as replacement for both pressure classes.
• RKV4G37DVR35IDR — Gymatic VR35 with integrated injector and IDR suffix. Two-mode with IDR component. Verify IDR role with AR North America.

Key Specifications

RKV4G37D-F24C2I Technical Details at a Glance

• Flow Rate: 4.0 GPM (gallons per minute)
• Maximum Pressure: 3,700 PSI
• Cleaning Units: 14,800 (GPM × PSI)
• Operating Speed: 3,400 RPM
• Pump Type: RK Series triplex ceramic plunger pump — three-piston crankshaft-driven design for smooth, consistent high-pressure output
• Crankshaft Bore: 1″ hollow keyway — direct engagement with gas or diesel engine 1″ output shaft
• Crankcase: Reinforced — heavy-duty construction for continuous commercial duty operation
• Manifold Material: Forged brass — dense, pore-free construction for corrosion resistance and sustained high-pressure cycle integrity
• Plungers: Solid ceramic — exceptional hardness, wear resistance, and thermal shock resistance across extended commercial operating hours
• Connecting Rods: Bronze — premium fatigue strength and wear resistance at 4.0 GPM / 3,700 PSI continuous duty cycles
• Valves: Stainless steel — precise seating geometry, scale resistance, and reliable performance under continuous cycling
• Serviceability: Front-access piston packings and valve assemblies for simplified field maintenance
• Lubrication: Oil-bath crankcase lubrication with vented dipstick and sight glass
• Flange: F24 — SAE J609A direct-drive flange for RK Series ‘D’ version, 1″ shaft, gas and diesel engine compatible (AR part AR41866)
• Unloader System: Gymatic (C2 code) — brass-body internal bypass unloader with integrated downstream chemical injector, adjustable pressure regulation
• Chemical Injector: Included — downstream venturi injector integrated into Gymatic unloader assembly (“I” suffix confirmed)
• Warranty: 5-year limited warranty — US-based coverage through AR North America

What’s Included in the Box

A Complete, Factory-Configured RKV4G37D-F24C2I Assembly Ready for Installation

Every RKV4G37D-F24C2I ships fully assembled, factory-tested for flow, pressure, and seal integrity, and field-ready:

• Factory-installed Gymatic unloader (C2) with active chemical injector — pre-mounted and calibrated with integrated downstream injector ready for detergent supply line connection
• AR factory break-in oil — crankcase pre-filled to the correct operating level for first startup without modification
• Vented dipstick — fast, accurate crankcase oil level checks with proper crankcase pressure relief
• Clear oil sight glass — at-a-glance visual verification of crankcase lubrication level
• Mounting bolts and fasteners — hardware sized for F24 SAE J609A direct-drive flange installation on compatible 1″ shaft gas or diesel engines
• Operator’s manual — complete installation, startup, operating, and maintenance procedures for the RKV4G37D-F24C2I including oil change intervals, packing and valve service guidance, chemical injector care, and winterization protocol
• Parts schematic — exploded-view diagram with AR part numbers for every serviceable RKV4G37D-F24C2I component
• Factory test certification — every RKV4G37D-F24C2I load-tested at 50%, 100%, and 150% of rated output before leaving the AR manufacturing facility

Gymatic Unloader with Integrated Chemical Injection — Two-Mode 3,700 PSI Wash Platform

Pre-Soak, Degrease, and 3,700 PSI / 4.0 GPM Rinse Through the RKV4G37D-F24C2I

The Gymatic unloader (C2) with integrated downstream injector on the RKV4G37D-F24C2I provides both pressure regulation and chemical feed capability through a single factory-assembled unit:

• Adjustable bypass regulation — the C2 Gymatic on the RKV4G37D-F24C2I senses line pressure and diverts flow to bypass as needed, maintaining consistent working pressure at the gun and protecting hoses, spray guns, and accessories from over-pressurization at trigger release
• Tamper-resistant once set — locked operating pressure maintained consistently across every operator and every job cycle on the RKV4G37D-F24C2I without re-adjustment or drift
• Smooth internal bypass at 4.0 GPM — trigger-off bypass redirects the full 4.0 GPM flow at 3,700 PSI, preventing deadhead pressure spikes during idle intervals on production wash jobs
• Venturi-driven downstream injection — the injector integrated into the C2 Gymatic body draws detergent, degreaser, or pre-soak solution from a supply container when the RKV4G37D-F24C2I operator switches to low-pressure application mode. No separate injector hardware required.
• Two-mode workflow at 4.0 GPM / 3,700 PSI — chemical pre-soak breaks down contamination on fleet vehicles, industrial machinery, and large commercial surfaces; full 3,700 PSI / 4.0 GPM rinse at 14,800 cleaning units removes loosened material efficiently. The 4.0 GPM flow rate rinses more surface area per minute than 3.0–3.5 GPM alternatives, reducing total wash cycle time on large-surface production jobs.
• No separate injector hardware required on the RKV4G37D-F24C2I — the complete two-mode system is factory-assembled. One assembly. Two operating modes.
• Injector maintenance — flush the RKV4G37D-F24C2I injector circuit with clean water after every detergent session to preserve long-term venturi function as detailed in the included operator’s manual.

RK Series Construction — Built for High-Volume Continuous Commercial Duty

Solid Ceramic. Forged Brass. Bronze Connecting Rods. Front-Access Service.

• Solid ceramic plungers in the RKV4G37D-F24C2I resist abrasion, thermal shock, and chemical attack across extended commercial operating hours at 3,700 PSI. Individual replacement when service limits are reached — no full pump replacement required.
• Bronze connecting rods distribute mechanical load evenly across the crankshaft of the RKV4G37D-F24C2I, improving fatigue resistance and stabilizing the rotating assembly under the sustained high loads of 4.0 GPM / 3,700 PSI continuous commercial operation
• Reinforced crankcase on the RKV4G37D-F24C2I supports crankshaft, bearing, and connecting rod alignment while maintaining structural rigidity under vibration and thermal expansion cycles during continuous duty operation
• Forged brass manifold provides a dense, pore-free pressure vessel for sustained high-pressure cycling and corrosion resistance in commercial cleaning environments
• Stainless steel valves maintain precise seating geometry through high-cycle 3,700 PSI / 4.0 GPM operation, resisting calcium scale and pitting that cause pressure loss over time
• Triplex three-plunger design produces smooth, overlapping pressure pulses that reduce pulsation-induced fatigue stress on hoses, spray guns, surface cleaners, and fittings connected to the RKV4G37D-F24C2I

Front-Access Serviceability — RK Series Maintenance Advantage

Packing and Valve Service Without Full Disassembly

• Front-access piston packings — packing replacement on the RKV4G37D-F24C2I is accessible from the front of the pump without requiring full crankcase disassembly, reducing the time and labor required for the most frequent seal maintenance event in high-cycle commercial operation
• Front-access valve assemblies — inlet and outlet valve inspection and replacement accessible without removing the RKV4G37D-F24C2I from the engine mount in most installations, enabling valve service during scheduled maintenance windows
• Reduced maintenance downtime — shorter service windows translate directly into faster return to productive operation for contractor rigs and commercial wash operations running the RKV4G37D-F24C2I at high output daily

F24 SAE J609A — Direct Drive for Gas and Diesel Engines at 3,700 PSI

• Gasoline engine compatibility — direct bolt-up to commercial gas engines with a 1″ cylindrical output shaft and SAE J609A bolt pattern in the horsepower class appropriate for 4.0 GPM / 3,700 PSI loads on the RKV4G37D-F24C2I. Verify engine horsepower before installation.
• Diesel engine compatibility — equally compatible with standard diesel engines equipped with a 1″ crankshaft and SAE J609A bolt pattern for contractor rigs and industrial equipment
• Direct close-coupling — the RKV4G37D-F24C2I mounts face-to-face against the engine with the 1″ hollow keyway crankshaft bore engaging the engine shaft directly, eliminating belt guards, pulleys, and tensioning hardware
• Compact installation envelope — direct coupling reduces skid and trailer frame dimensions for portable contractor rigs at this output level
• Included mounting hardware — bolts and fasteners sized for the F24 SAE J609A bolt pattern are supplied in the box with the RKV4G37D-F24C2I

Typical Applications

Where the RKV4G37D-F24C2I Delivers Best Results

• Professional pressure washing contractors — two-mode wash workflow combining 3,700 PSI / 4.0 GPM rinse with Gymatic-integrated chemical pre-soak through the RKV4G37D-F24C2I for concrete cleaning, building exterior washing, surface preparation, and commercial property maintenance
• Equipment wash bays and industrial facilities — continuous or frequent-duty 3,700 PSI output from the RKV4G37D-F24C2I with integrated degreaser capability for production equipment, manufacturing machinery, and plant surfaces
• Fleet and vehicle washing — trucks, trailers, buses, and municipal vehicles where 4.0 GPM coverage speed and 3,700 PSI cleaning force with chemical pre-treatment handle heavy road film and grease on large fleet surfaces efficiently
• Construction and rental equipment — skid steers, excavators, loaders, and jobsite machinery where the RKV4G37D-F24C2I’s 3,700 PSI and integrated chemical capability handle maximum contamination on equipment returned from the field
• Concrete and hard surface cleaning — parking lots, loading docks, sidewalks, and warehouse floors where 14,800 CU output with integrated chemical application provides productive commercial cleaning results
• Agricultural operations — tractors, harvesters, implements, and barn sanitation on gas or diesel engine-powered rigs where high-volume output and chemical pre-soak capability are both required
• OEM rig builders and system integrators — the RKV4G37D-F24C2I’s F24 direct-drive mounting, integrated chemical injection, and simplified plumbing requirements support compact, efficient system designs for new builds and upgrades

5-Year US Warranty, Full Rebuildability, and Wholesale Pricing

High-Output RK Series Performance Backed by Domestic Support

The RKV4G37D-F24C2I is protected by Annovi Reverberi’s 5-year limited warranty through AR North America’s US-based warranty and service network. Every internal wear component of the RKV4G37D-F24C2I — solid ceramic plungers, bronze connecting rods, forged brass manifold seals and o-rings, stainless valve seats and springs, Gymatic unloader service parts, piston packing kits, and crankcase bearings — is stocked domestically through AR’s authorized distribution channels.

With consistent maintenance — break-in oil change at 50 hours, scheduled oil changes every 500 hours or 3–5 months, regular valve and packing inspection using the front-access design, chemical injector circuit flushing with clean water after every detergent session, and proper winterization using RV-grade environmentally safe antifreeze — the RKV4G37D-F24C2I is engineered for 10 or more years of productive commercial service life. AR North America’s domestic parts depth ensures rebuild kits, plunger sets, packing kits, and Gymatic unloader service components for the RKV4G37D-F24C2I are typically available same-week.

Contractors, rental fleet operators, municipal purchasing departments, resellers, and volume buyers are invited to contact wholesale@wshpwr.com for wholesale and special pricing on the RKV4G37D-F24C2I and the complete Annovi Reverberi pump and unloader assembly line. WSHPWR maintains one of the most complete AR North America inventories available through any US web store — with thousands of AR products in stock and a continually expanding catalog.

14,800 Cleaning Units. 3,700 PSI. 4.0 GPM. RK Series. Gymatic Bypass. Integrated Chemical Feed.

Italian Engineering. High-Volume Two-Mode Platform. Front-Access Service. US Warranty Coverage.

For contractors, equipment wash bay operators, fleet managers, and OEM system builders who need 4.0 GPM high-volume output at 3,700 PSI — with integrated Gymatic bypass pressure regulation and downstream chemical injection capability, RK Series reinforced crankcase with front-access piston packing and valve serviceability, bronze connecting rods, and a compact F24 direct-drive installation — the RKV4G37D-F24C2I delivers a factory-tested, fully documented, and completely rebuildable assembly from one of the global pressure pump industry’s most trusted manufacturers. Fourteen thousand eight hundred cleaning units. Direct drive. One-inch keyway shaft. Gymatic bypass with integrated injector. Front-access service design. Five years of US warranty. A decade of service life.

Volume buyers, resellers, and rental fleet operators can reach the WSHPWR wholesale team directly at wholesale@wshpwr.com to discuss pricing for quantity purchases across the complete Annovi Reverberi lineup — including pumps, unloader assemblies, and service parts.