Marine Air Flow International

Air-On-Demand System

Air-On-Demand 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" Fan Controller

This Pulse Width Modulation (PWM) DC motor controller can provide up to a maximum continuous current of 50A to your DC motor or other DC load, thanks to a digital micro-controller based (PIC) design and highly efficient High-Power 202A MOSFET for cooler operation.

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 50%. The idle speed is easily adjusted onsite via the single potentiometer knob on 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 1 controller per 2 x 12volt DC fans or per 3 x 24volt DC fans.

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" Fan Controller

Fully automatic controller designed to regulate speed of you engine room fans. It can be controlled at the bridge through a switching (on/off) NO temperature probe in the controller that measures the engine room temperature and directly varies the speed in relation to that temperature. Low temperature = low speed fan, high temperature = high speed fan.

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

The fixed speed is pre-set at 50%, but is adjustable if required. The fixed speed at 50% 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. NB: the fixed speed maybe adjusted to a custom level if required.

We stock these common sizes:

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

These are fully programmed and bench tested with installation schematics.

Sub 30 degrees  preset idle 40% approx. 30-40 adjust incrementally. 40+ 100%

Reduced noise at low demand and reduce power at low demand.

AC Air-On-Demand - 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