AC Infinity CLOUDLINE PRO S4 4" Inline Duct Fan — Quiet 205 CFM, Wired 10-Speed Controller

The AC Infinity CLOUDLINE PRO S4 is a compact, quiet 4-inch inline duct fan built for efficient ventilation with a wired 10-speed controller and PWM EC motor.

Designed for small grow tents, home ventilation runs, AV rack cooling, and general air transfer, the S4 balances high airflow with low noise and energy use. Its mixed-flow impeller and stator blade design push air effectively through restrictive ducting while dual ball bearings extend service life. The included wired 10-speed controller gives direct manual control and the fan remains compatible with AC Infinity's UIS ecosystem for advanced automated profiles.

How does the fan stay quiet while moving air?

The S4 uses a PWM-driven electronically commutated (EC) motor that runs efficiently at lower temperatures and produces less vibration. A mixed-flow impeller with hydrodynamic blade geometry reduces turbulence so the fan keeps airflow high without loud whine.

• PWM EC motor minimizes electrical noise and heat build-up.
• Mixed-flow fan design reduces air turbulence for smoother sound.
• Dual ball bearings lower mechanical friction and vibration.
• Measured noise level: approximately 28 dBA at rated conditions.

What environments and setups is this fan best suited for?

Its compact 4-inch duct size and 205 CFM capacity make the S4 ideal for small to medium enclosed spaces where restricted duct runs or noise are concerns. Use it for ventilating grow tents, moving conditioned air between rooms, exhausting odors, or supplementing AV cabinet airflow.

• Grow tents and small indoor gardens where space is limited.
• Inline ventilation for bathroom or utility room duct runs.
• Cooling electronics, AV racks, and home networking cabinets.
• Exhausting odors or circulating conditioned air in tight ducts.

How do I control speed and automation options?

The fan ships with a wired 10-speed controller for immediate manual adjustments. For automated schedules, temperature, or humidity-based control, the CLOUDLINE PRO S4 integrates with AC Infinity's UIS controllers and accessories, enabling intelligent programming and environmental triggers.

• Included wired 10-speed knob for quick, precise speed changes.
• Compatible with UIS series controllers for automated profiles.
• PWM input allows clean, responsive speed modulation from controllers.
• Works with common smart ventilation setups when paired with UIS devices.

What are the key specifications I should check before buying?

Confirm duct size compatibility and that the fan's airflow and sound levels meet your project needs. The S4's compact footprint and performance numbers help determine fit for tight installations or ducted systems with resistance.

• Duct diameter: 4 inches — fits standard 4" ducting and adapters.
• Dimensions: 6.9 x 11.9 x 7.4 inches — compact inline profile.
• Airflow: 205 CFM — suitable for small to medium ventilation tasks.
• Noise: ~28 dBA — low acoustic signature for discreet use.
• Bearings: Dual ball bearings for longer mechanical life.

Who is this for? The CLOUDLINE PRO S4 is aimed at hobbyist growers, DIY home ventilators, and AV or electronics enthusiasts who need a small, quiet inline fan with precise speed control. If you want high airflow from a 4" duct fan with low noise, energy-conscious motor technology, and the option to expand into AC Infinity's UIS automation platform, the S4 is a sensible choice. For larger rooms or higher static pressure systems, consider stepping up to a larger diameter model to match required airflow and duct resistance.