ASV instructions


Tools and materials needed
  • • drill with 3/16” bit
  • • hacksaw
  • • 4” holesaw (or other means of making hole through wall)
  • • phillips screwdriver
  • • ASV hardware packet (provided with ventilator)

Locate an area on an outside wall that can accommodate a four inch round hole which is free of framing members, heat ducts, wiring and other obstructions. Make the hole through the wall, and insert one of the tubes until it is flush with the outside wall. Mark any excess that protrudes into the room with a pencil and cut it off with the hacksaw. For deeper walls, the second tube may be needed.

Seal the tube to both interior and exterior walls with the rope caulking provided in the hardware packet. Try to avoid getting the caulking inside the tube. Fasten the exterior grille assembly to the outside wall with four of the screws from the hardware packet.

Place the interior damper assembly into the inside hole and mark the location of the four holes on the wall. Remove the damper assembly and drill four 3/16” holes at the marked spots. Insert the plastic anchors from the hardware packet and fasten the damper assembly with the remaining four screws from the hardware packet. Slip the damper slide control into the channel at the bottom of the damper assembly and check its operation. Place the insulated cap onto the mounted damper assembly, and the ASV-90 is ready to use.

Minimum air settings

To establish a constant low volume airflow, even when the damper is closed, remove the clear plastic plug on the damper. Removing one or more of the concentric rings surrounding the plug with a sharp knife can increase the minimum airflow.

Note: Where ventilation is required by state or local codes, it may be necessary to remove the entire damper assembly to insure an uninterrupted source of ventilation air. To remove the damper assembly, squeeze the round end of the interior controller to slightly elongate it on an up/down axis. The damper hinge posts can then be disengaged from the body of the controller. Remove the entire damper assembly and slide control. Place the insulated cap onto the modified interior wall mounting.


The foam dust filter should be removed twice yearly (or as needed) and washed in warm soapy water. Pollen and High Tec filters will need to be replaced when clogged, as washing will remove the electrostatic charge that makes them effective. The tube should be inspected regularly for obstructions, and the exterior insect screen should be removed and cleaned as needed.


Special Pollen Filter (part # ASV-10) can be substituted for the standard dust filter. Removes 90% of pollutants over 5 microns in size. Use of this filter will somewhat reduce airflow, necessitating the damper be more fully open than with the dust filter.

High Tec Filter (part # ASV-60) can be substituted for the standard dust filter. Removes very small particles of halfmicron size and up. Use of this filter will greatly reduce airflow, necessitating that the damper be kept fully open when in use.

Automatic Storm Shield (part # ASV-4) closes the ventilator automatically in high winds or in extreme pressure differentials (18 Pascal or greater). Recommended in areas of high wind or above the third story in high rise buildings.

Pressure Guard (part # ASV-41) Allows air to flow only in one direction. Prevents air escaping from the house through ventilator.

Wall Cover Plates(parts #s ASV-11 & ASV-12) may be used to cover larger wall openings on either interior or exterior walls. Available in 6 ½” (ASV-11) or 8 ¼” (ASV-12) sizes.