The Graco 15B438 Pressure Knob delivers precision control for demanding jobs, making it an essential accessory for contractors. Engineered to integrate with Graco pumps, this compact component optimizes flow rates to ensure consistent coverage on tough surfaces. Its ergonomic design simplifies adjustments in the field and enhances productivity. Ideal for modern finishing systems and airless sprayer applications.
Built from durable materials, the 15B438 knob improves the lifespan of seals and valves by enabling smooth, incremental pressure changes that are vital when applying professional coatings. Its universal compatibility with Graco equipment and straightforward installation make it a reliable choice for technicians. Use this part to maintain high standards in versatile spraying operations requiring precise pressure control and effective high-pressure filtration.
The Graco 15B438 Pressure Knob is an OEM replacement component engineered for precise regulation of hydraulic pressure within Graco pump modules. This compact assembly measures 2 × 0.2 × 0.2 inches and weighs just 0.3 lb, making it suitable for both portable and stationary spray systems. The knob directly interfaces with the regulator stem to adjust the set-point pressure from 500 to 3000 psi, providing an uninterrupted feedback loop to maintain consistent fluid delivery. Its low-profile design reduces inert volume in the fluid channel, minimizing residual paint waste during color changes. Tested for operating temperatures from –20 °C to +80 °C, the unit demonstrates robust performance in extreme environments. By enhancing component response time and reducing pressure overshoot, it contributes to improved pump efficiency and extended service intervals. Operators in the field can rely on the refined detent mechanism for repeatable click-index adjustments without drift or slippage under load. airless sprayer specialists leverage this knob to balance flow rates and achieve uniform coating thickness across complex geometries.
Typically mounted directly onto the pump’s regulator post, the knob employs a spiral bevel interface that converts rotational input into linear motion on the valve piston. The dial’s interior features a 36-tooth gear ring mated to a helical cam, providing a consistent torque-to-pressure ratio with minimal hysteresis. Material selection includes an ABS-based thermoplastic dial with UV stabilization and a 316 stainless-steel shaft, both validated under ISO 9001 quality protocols. The integrated EPDM and Viton seals create dual barriers against fluid bypass and particulate ingress, optimizing high-pressure filtration performance in the fluid loop. In professional coatings operations, this results in stable output pressure even under rapid cycle rates, eliminating spray defects such as fisheyes or back-banding. Calibration can be conducted in situ using a high-precision digital gauge to confirm the linear correlation between rotation and pressure set-point. Each unit undergoes a factory calibration check with traceability to NIST standards, ensuring consistent performance across production batches. Maintenance access is simplified through a snap-fit collar, allowing technicians to replace wear components without special tooling.
In laboratory test benches, the 15B438 Pressure Knob exhibited a linear pressure response with a non-linearity deviation of less than 1.5% over the 500–3000 psi range. Hysteresis was measured at under 0.8% of full-scale output during reverse rotation tests, demonstrating exceptional repeatability. Dynamic response trials indicated a settling time of under 25 ms for a 100 psi step change, critical for controlling pulsed injection modes. Temperature chamber testing from –40 °C to +90 °C showed less than 0.05% drift per degree Celsius, validating thermal stability in extreme climates. The knob’s detent mechanism endured over 200,000 actuation cycles with negligible wear, confirming long-term durability. Impact tests simulating 5 g lateral shock loads produced no functional anomalies. Moreover, integration into high-pressure filtration loops can reduce particulate ingress by enabling real-time pressure drop monitoring across filter cartridges. Quality assurance records detail test protocols, including C-factor analysis and life-cycle stress screening, aligning with ANSI/ASME instrumentation standards.
The Graco 15B438 knob is engineered for straightforward maintenance and minimal downtime. Disassembly requires only a 5 mm hex tool to remove the retaining screw and access internal seals, springs, and bearings. For maximizing seal longevity, technicians should apply a light film of FDA-approved silicone grease on EPDM and Viton seals before reassembly, and visually inspect for nicks or hardening at each preventive maintenance interval. The knob’s anti-cross-threading feature ensures smooth installation on the regulator post, while the optimized O-ring gland reduces stress concentrations that can lead to premature failure. These design considerations facilitate rapid field service and uphold system integrity in abrasive or solvent-laden environments.
By integrating the Graco 15B438 Pressure Knob into your fluid delivery and control architecture, engineers and operators gain superior granularity over fluid pressure profiles, enabling fine-tuning for varied viscosity media. The component’s repeatable setting retention supports complex multi-component mixing systems, while its alignment with Graco’s quality standards underpins reliable performance in critical operations. Whether deployed in airless sprayer circuits, automated dispensing equipment, or high-flow processing lines, the knob plays an essential role in achieving uniform coverage, preventing material waste, and extending service life of downstream components. Proper installation torque (1.5–2 N·m) and adherence to recommended maintenance cycles will ensure peak functionality and hassle-free operation.
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