Performance test for cabinet insert models (ducted)

In most cases, noise or suction issues are related to how the ductwork is installed. No worries — we're here to help ensure everything is set up correctly so your unit performs at its best.

Steps to Diagnose Suction or Noise Issues

1. Remove the baffle filters (the stainless steel grills) to expose the blower motor.

   • The blower sits in the center of the unit and will be visible once the baffles are out.

2. Prepare two paper towels large enough to cover both fan grills.

3. Turn the unit on speed two or three, and hold the paper towels over the fan grills:

   • If the towels stick flat to the grills: The damper blades are opening properly. That’s a good sign — but we’ll still want to confirm that your duct setup is optimized for maximum airflow.

   • If the towels flutter or fall: The blades may not be opening fully, or there may be a blockage somewhere in the duct system.

4. Next step: Open the cabinet doors to access the ductwork.
5. Detach the duct from the unitand repeat the paper towel test:
   • If the towels now stick flat: The issue lies within the ducting or damper.
   • If they still flutter: The problem is likely within the unit itself.

Duct Setup Guidelines for Best Performance

Use consistent duct size, shape, and material

• Stick with 6" round, or transition to 7" for longer runs.

• Avoid reducing size, changing shape, or mixing materials (e.g., switching from round to rectangular).

• Best practice: Use semi-rigid or rigid ducting.

Keep ducting short and straight

• Max total length: 14 feet.

• Include at least 12 inches of straight ducting coming directly out of the top of the unit before any bends.

Avoid airflow restrictions

• Minimize 90-degree turns
  

• Don’t use flexible ducts — they can become scrunched up and restrict the damper blades from opening.

• Do not reduce duct size — reducing from 6" to 4" significantly reduces performance and increases noise.

Tips

• Remove damper blades: If your home already has an external roof or wall cap with dampers, you may consider removing the internal damper blades to improve suction and reduce noise.

• Do not reduce duct size: Reducing the duct from 6" to 4" significantly reduces performance and increases noise.

• Avoid flexible ducting: If used, ensure it’s not scrunched up. This can restrict the damper from working properly. Rigid or semi-rigid ducts are always preferred.

• Keep transitions to three or less: Each turn in your ductwork creates airflow resistance. To maintain optimal performance and minimize noise, limit elbows and direction changes to a maximum of three.