Clothes dryer with its vent duct in a small laundry closet
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Measuring dryer vent restriction: airflow and back-pressure basics

A restricted vent is the most common cause of slow drying and blown thermal fuses, and failure to clean is the leading factor in residential dryer fires (USFA). Check the run against code and the manufacturer's limits, compare airflow at the termination, and measure back-pressure only against the manufacturer's spec.

Cross-checked ~30 min easyBrands: All

Before you start

  • Gas dryers: a blocked or disconnected vent can push CO into the home; refer gas-side issues
  • Unplug before pulling the dryer out or touching the duct

Diagnostic steps

Unlock all 5 steps with expected values

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OnCall Tech is a reference tool for trained technicians and can make mistakes. Always disconnect power and confirm with the manufacturer's documentation before you work.

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Measuring dryer vent restriction: airflow and back-pressure basics · OnCall Tech