Dexon Canada Ventilation Equipment
- Outdoor Flange Mount -

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The SMVOD Vent Fan is designed to run continuous to provide positive pressure safety ventilation where heated air is not required at a preset adjustable idle speed to ensure ventilation is available when required by preventing freeze up and corrosive damage to the fan.  The operator is then able to flush ventilate prior to entering a confined space. Provisions for a Low Temp shut down is provided for an optional thermostat interface. The Low Temp shut down will occur when the temperature drops below the normal operating range as set on site.  When the temperature increases the fan will go from shut down to boost start, which provides full voltage to the fan to ensure start up. The preset idle speed is then maintained until manually switched to high speed with a toggle switch. The toggle switch will also override a low temp condition.


Solid State controller designed and manufactured by Dexon provides the following features:

  • FAN SPEED CONTROL- On board potentiometers are provided on the controller to preset and adjust both hi and low speed settings
  • FAN BOOST START - A full voltage boost start is applied to the fan upon startup before the fan goes into its preset idle speed to ensure a startup in low speed mode and after a low temp condition subsides
  • LOW TEMP SHUT DOWN A set of terminals is provided to interface with a normally closed thermostat contact to completely shut down the fan when the temperature drops below normal operating range as set on site. This occurs only when the fan is in low/idle speed; max speed will override the low temp. shut down
  • PROOF OF ROTATION SET POINT - A potentiometer is provided on the controller to set the point at which indication of rotation is desired for  “ Blower NO 1" and “Blower NO. 2" (if used) LED on the status indicator
  • STATUS INDICATOR - A Status Indicator/Controller to be mounted remote in a suitable enclosure provides the following indications by way of LEDs:

“Power On” -Indicates that control power is present at main controller
“Low Temp.” - indicates that the Low Temp Shut Down has been activated 
Blower No.1" - indicates proof of blower No. 1 rotation by way of a tachometer output signal from the fan to the status indicator
Blower No.2" (if used)- indicates proof of blower No.2 rotation by way of a tachometer output signal from the fan to the status indicator

PWM Status Board Status Info


    1. “Blower NO.1 and Blower NO. 2” indicate poof of blower rotation, by way of a tachometer output signal from the fan to the status indicator. This is not proof of air, rather an indication of motor running
    2. High Low Switch” - a manual switch is provided to switch the fan to max speed . The normal operation position for the switch is on low. Do not leave switch on high unattended


  • 120 Volt, 60 Hz input to Vent Fan
  • Low voltage interfacing between vent fan and status indicator/controller (cable provided)
  • Power consumption based on blower(s)
  • Class 1, Div.2, Location units must be fused remote in a non-hazardous location
  • Ordinary location fused internally


  • Typical discharge is round flat bottom with gasket supplied, diameter based on capacity
Power Low Temp Blower No.1 Blower No.2 Warning High - Low Switch
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Copyright © 2011 Dexon Canada Air Systems Inc.