RKV4G37DF24VR35 4.0 GPM 3700 PSI Triplex Pump | VR35

RKV4G37DF24VR35 by Annovi Reverberi — RK Series Triplex Plunger Pump with Gymatic VR35 Unloader | 4.0 GPM | 3,700 PSI | Bronze Connecting Rods | 1″ Hollow Keyway Shaft | SAE J609A Gas and Diesel Engine Drive | No Chemical Injector

The RKV4G37DF24VR35 by Annovi Reverberi is a commercial-grade RK Series triplex ceramic plunger pump engineered for gas and diesel engine-driven industrial, fleet, contractor, and commercial pressure washing systems requiring high-volume 4.0 GPM output at 3,700 PSI with dependable Gymatic VR35 bypass pressure regulation and straight high-pressure water delivery. Rated at 4.0 GPM and 3,700 PSI at 3,400 RPM, the RKV4G37DF24VR35 delivers 14,800 cleaning units — combining the high-volume coverage speed of 4.0 GPM with 3,700 PSI pressure output that penetrates heavy contamination more aggressively than standard 3,000–3,200 PSI commercial platforms — through a reinforced aluminum crankcase with bronze connecting rods, solid ceramic plungers, and an F24 SAE J609A direct-drive flange for close-coupling to gasoline or diesel engines.

The RKV4G37DF24VR35 is the no-injector, no-IDR configuration of the RKV 3,700 PSI platform — the correct specification for operators managing chemical delivery through a dedicated external downstream injector, soft wash system, or operating on straight high-pressure water output. The Gymatic VR35 unloader on the RKV4G37DF24VR35 is rated to 4,000 PSI and 5 GPM — operating with 300 PSI of comfortable headroom above the 3,700 PSI output for stable, well-regulated bypass performance well within the VR35’s rated envelope.

Built by Annovi Reverberi in Modena, Italy — with US-based operations, a domestic parts distribution network, and dedicated AR North America technical support — the RKV4G37DF24VR35 arrives as a complete, factory-tested assembly. Pre-filled with AR break-in oil, equipped with a Gymatic VR35 unloader, 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 RKV4G37DF24VR35 is a long-term investment in a high-output RK Series commercial pump platform capable of a decade of productive service life.

Decoding the RKV4G37DF24VR35 Model Number

What Every Segment of This AR Pump Designation Tells You

The RKV4G37DF24VR35 encodes pump series, output, shaft type, flange interface, and unloader family directly. Reading each segment confirms RK Series platform, engine compatibility, and full pump configuration:

• RKV — Pump series: RK Series triplex plunger pump — AR’s industrial pump platform built around a reinforced aluminum crankcase with front-access piston packing and valve serviceability for continuous industrial 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 via F24 SAE J609A face flange
• 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)
• VR35 — Unloader system: Gymatic VR35 — AR’s elevated-capacity Gymatic internal bypass unloader rated to 4,000 PSI and 5 GPM. At 3,700 PSI the VR35 provides 300 PSI of operating headroom — stable, responsive bypass regulation well within the rated envelope.
• No trailing I, DR, or IDR suffix — the model terminates at VR35, confirming standard VR35 bypass operation without a downstream chemical injector and without an IDR component. This pump delivers straight 3,700 PSI / 4.0 GPM water output.

RKV4G37DF24VR35 vs RKV4G37DVR35IDR — The RK Series 3,700 PSI Platform Variants

Both pumps share the same RK Series platform, F24 flange, 1″ hollow keyway shaft, reinforced aluminum crankcase, bronze connecting rods, front-access serviceability, and Gymatic VR35 unloader at 4.0 GPM / 3,700 PSI / 14,800 CU. The difference is injector and IDR status:

• RKV4G37DF24VR35 (this model) — Gymatic VR35, no chemical injector, no IDR suffix. Straight 3,700 PSI water output for external chemical management or clean water-only applications.
• RKV4G37DVR35IDR — Gymatic VR35 with integrated downstream chemical injector and IDR suffix. Two-mode wash capability with chemical pre-soak and 3,700 PSI rinse. Verify IDR suffix role with AR North America before installation.

Key Specifications

RKV4G37DF24VR35 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 aluminum — heat-dissipating architecture for thermal stability during continuous high-RPM 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, RK Series ‘D’ version, 1″ shaft, gas and diesel engine compatible (AR part AR41866)
• Unloader System: Gymatic VR35 — brass-body internal bypass unloader, adjustable pressure regulation, rated to 4,000 PSI and 5 GPM; 300 PSI operating headroom above 3,700 PSI output
• Chemical Injector: Not included — model terminates at VR35 with no injector suffix
• Warranty: 5-year limited warranty — US-based coverage through AR North America

What’s Included in the Box

A Complete, Factory-Configured RKV4G37DF24VR35 Assembly Ready for Installation

Every RKV4G37DF24VR35 ships fully assembled, factory-tested for flow, pressure, and seal integrity, and field-ready:

• Factory-installed Gymatic VR35 unloader — pre-mounted and calibrated for field-ready operation; no downstream injector port on this RKV4G37DF24VR35 variant
• 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 RKV4G37DF24VR35 including oil change intervals, packing and valve service guidance, and winterization protocol
• Parts schematic — exploded-view diagram with AR part numbers for every serviceable RKV4G37DF24VR35 component for field and shop reference
• Factory test certification — every RKV4G37DF24VR35 load-tested at 50%, 100%, and 150% of rated output before leaving the AR manufacturing facility

The Gymatic VR35 at 3,700 PSI — Stable Bypass with 300 PSI Headroom

Well Within Rated Envelope. Tamper-Resistant. Clean Water Output.

The Gymatic VR35 unloader on the RKV4G37DF24VR35 is rated to 4,000 PSI and 5 GPM — operating with 300 PSI of headroom above the pump’s 3,700 PSI output:

• Comfortable operating margin — the VR35 at 3,700 PSI operates 300 PSI below its rated ceiling, producing confident, stable bypass regulation behavior. The RKV4G37DF24VR35’s unloader remains responsive and consistent across continuous production wash cycles without the elevated internal stress of near-ceiling operation.
• Extended unloader service life — bypass valve components and seating surfaces operating with 300 PSI of headroom experience less cumulative stress than at maximum-rated pressure, extending the rebuild interval on the RKV4G37DF24VR35 in high-cycle commercial environments
• Adjustable then tamper-resistant — locked operating pressure maintained consistently across every operator, every shift, and every production wash cycle without re-adjustment or drift
• Smooth internal bypass at 4.0 GPM — trigger-off bypass smoothly redirects the full 4.0 GPM flow at 3,700 PSI, preventing deadhead pressure spikes that accelerate seal and valve wear during idle intervals on production jobs
• No downstream injector port — the RKV4G37DF24VR35 delivers straight 3,700 PSI / 4.0 GPM water output. Chemical delivery managed externally through a dedicated downstream injector, soft wash proportioner, or separate chemical system.
• Engine load reduction in bypass — reduced back-pressure lowers engine load and fuel consumption during trigger-off idle intervals on full-day wash operations
• Brass body construction — resists corrosion from cleaning chemicals, chlorinated water, and sustained outdoor field exposure

Why No Chemical Injector Is the Right Specification for Many RKV4G37DF24VR35 Applications

External Chemical Control. Full Ratio Flexibility. Maximum System Design Freedom.

• Adjustable-ratio external downstream injectors — operators running independently adjustable downstream injectors gain chemical concentration flexibility that a fixed venturi injector cannot provide. At 3,700 PSI, precise chemical management improves cleaning results on varying surfaces and contamination types independently of the RKV4G37DF24VR35 pump setting.
• Soft wash and proportioner systems — soft wash operations managing chemical delivery through dedicated proportioning pumps or batch tanks keep the RKV4G37DF24VR35 as a clean high-pressure water supply source, maintaining independent chemical control at any dilution ratio
• Multi-pump industrial systems — OEM integrators building systems with multiple RKV4G37DF24VR35 pump heads standardize chemical injection at the system level rather than managing individual pump-integrated injectors
• Standard bypass preference — operators and system builders who prefer standard VR35 internal bypass operation without additional IDR or injector components can specify the RKV4G37DF24VR35 as the clean, direct configuration at this output level

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

Reinforced Aluminum Crankcase. Bronze Connecting Rods. Front-Access Service.

• Reinforced aluminum crankcase — aluminum’s high thermal conductivity dissipates friction-generated heat more effectively during continuous high-RPM operation on the RKV4G37DF24VR35, maintaining lower operating temperatures at bearing and seal interfaces across extended duty cycles compared to iron or steel crankcase alternatives
• Bronze connecting rods resist the repeated load cycling of 4.0 GPM / 3,700 PSI operation at 3,400 RPM, providing the fatigue strength and wear resistance at bearing interfaces required for high-cycle commercial continuous duty on the RKV4G37DF24VR35
• Solid ceramic plungers resist abrasion and thermal shock at 3,700 PSI across extended commercial operating hours. Their dimensional stability maintains precision plunger geometry through thousands of duty cycles. Individual replacement when service limits are reached.
• 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 throughout the wash system connected to the RKV4G37DF24VR35

Front-Access Serviceability — RK Series Maintenance Advantage

Packing and Valve Service Without Full Disassembly

• Front-access piston packings — packing replacement on the RKV4G37DF24VR35 is accessible from the front of the pump without requiring full crankcase disassembly, reducing time and labor 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 pump from the engine mount in most installations, enabling valve service during scheduled maintenance windows rather than requiring full pump removal from the rig
• Reduced maintenance downtime — shorter service windows translate directly into faster return to productive operation for contractor rigs and commercial wash operations running the RKV4G37DF24VR35 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 RKV4G37DF24VR35. 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 RKV4G37DF24VR35 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
• Included mounting hardware — bolts and fasteners sized for the F24 SAE J609A bolt pattern are supplied in the box with the RKV4G37DF24VR35

Typical Applications

Where the RKV4G37DF24VR35 Delivers Best Results

• Professional pressure washing contractors with external chemical systems — 3,700 PSI / 4.0 GPM output from the RKV4G37DF24VR35 paired with independently managed detergent delivery for concrete cleaning, building exterior washing, surface preparation, and commercial property maintenance
• Fleet and vehicle washing — trucks, trailers, buses, and construction equipment where 4.0 GPM coverage speed and 3,700 PSI cleaning force handle heavy contamination efficiently with chemical applied through an external downstream system
• Industrial equipment washdown — manufacturing machinery, process equipment, and plant surfaces where the RKV4G37DF24VR35’s 3,700 PSI penetrates contamination more aggressively than standard 3,000 PSI platforms
• Concrete and hard surface cleaning — parking lots, sidewalks, loading docks, and warehouse floors where 14,800 CU high-volume output provides efficient production cleaning results with chemical applied externally
• Agricultural operations — tractors, harvesters, sprayers, and barn facilities on gas or diesel engine-powered rigs where maximum volume at elevated pressure handles large surface areas and heavy organic contamination
• Soft wash system rinse supply — the RKV4G37DF24VR35 provides clean 3,700 PSI / 4.0 GPM rinse water while a dedicated soft wash proportioner manages chemical delivery independently
• Mobile contractor rigs and OEM system builds — trailer and skid-mounted systems where the RKV4G37DF24VR35’s compact RK Series direct-drive footprint, front-access serviceability, and external chemical architecture support efficient daily field operations

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

High-Output RK Series Performance Backed by Domestic Support

The RKV4G37DF24VR35 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 RKV4G37DF24VR35 — solid ceramic plungers, bronze connecting rods, forged brass manifold seals and o-rings, stainless valve seats and springs, Gymatic VR35 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, and proper winterization using RV-grade environmentally safe antifreeze — the RKV4G37DF24VR35 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 VR35 unloader service components for the RKV4G37DF24VR35 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 RKV4G37DF24VR35 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. VR35 Bypass. External Chemical Control.

Italian Engineering. High-Volume Mid-High Pressure Platform. Front-Access Service. US Warranty Coverage.

For contractors, industrial operators, fleet managers, and system builders who need 4.0 GPM high-volume output at 3,700 PSI — with the Gymatic VR35 unloader operating comfortably within its rated envelope, clean straight water output for external chemical management, RK Series reinforced aluminum crankcase with front-access serviceability, and bronze connecting rods — the RKV4G37DF24VR35 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. VR35 bypass. No fixed 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.