Marine Air Flow International

Air-On-Demand System

Automatic Fan Speed Controllers

Air-On-Demand Fan Speed Controller:

Our Variable Speed Drive "Air-On-Demand" systems has been developed in house specifically for marine engine room applications.

Our Air-On-Demand systems are fully bench tested and pre-programmed ready for installation. They come complete with a control switch panel which includes a fault light & also include a full wiring diagram to aid in installation.  AC and DC versions are available.

Air-On-Demand Features

  • Automated fan speed based on temperature
  • Ideal for tourism vessels where sound levels are important - ideal for reduce noise and power
  • Available in AC or DC options
  • AC available in 240V or 3Phase

DC "Air-On-Demand" Auto Fan Speed Controller

This Pulse Width Modulation (PWM) DC motor controller can provide up to a maximum continuous current of 76A to your DC motor or other DC load.

The controller has one mode of operation. FIXED frequency. The fixed frequency runs the controller at 100Hz. Duty cycle is fully adjustable from 0% to 100%.

The controller also offers built-in soft-start feature that greatly reduces the mechanical stress on the motor as well as the electro-dynamic stress on the attached cables and battery, therefore extending the life span of the whole system. When power is connected to the circuit, the duty cycle will start from 0% and go up to the present value in about 1 to 1.5 seconds.

These units have a fully adjustable idle speed 0-100%, but are preset at our factory to 40%. The idle speed is easily adjusted onsite via the single potentiometer knob inside the control box. The fans will run at preset idle speed to 30 degrees Celsius. When the engine room reaches 30 degrees the fan speed automatically increases incrementally until 40 degrees Celsius. At or above 40 degrees Celsius the fans will run at 100% and remain at 100 % until the engine room temperature is reduced below 40 degrees.

We recommend a total of 4 x 12/24v DC Compact Fans per 1 controller.

DC Air-On-Demand - Spec Data Sheet

Click on the link below to download our DC Air-On-Demand Specifications  Sheet (Spec Data Sheet).

DC Air-On-Demand Sheet

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AC "Air-On-Demand" Auto Fan Speed Controller

You will start with a Licensed Electrician to install the AC systems. This system offers a fully automated control with a simple selector switch- AUTO/OFF/ MANUAL.   

The manual setting can be adjusted form 0-100%. The manual setting is utilised for maintenance periods in order to limit engine room noise. When the system is on AUTO and active, the controllers will directly vary the fan speed in direct relation to the Engine Room Temperature. This allows maximum performance at minimum power and sound levels, creating the ideal low noise work environment and allowing the best possible performance and protection of both crew and equipment. 

We stock these common sizes:

2.2Kw VSD (variable speed drive) 240v
2.2Kw VSD (variable speed drive) 3Phase

Custom size of 0.75Kw - 30Kw are available on request.

These are fully programmed and bench tested with installation schematics.

AC Air-On-Demand - Auto Fan Speed Controller Spec Data Sheet

Click on the link below to download our AC Air-On-Demand Specifications  Sheet (Spec Data Sheet).

AC Air-On-Demand Sheet

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Contact Us

Get in touch via phone, email or through our contact form and we will be pleased to assist with all your engine room ventilation needs. 


33-37 Paradise Avenue

Miami QLD 4220

6am to 4:30pm. Mon ~ Thurs


Mark:  office[at]

Brad:   info[at]


Mark:  +61 428 301 700

(Chief Estimator)

Brad:      +61 400 714 803