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Musty odor, mold

What is going on

Possible causes and checks for: musty odor, mold.

Likely causes

  • Moisture (leaks, condensation, damp basement)
  • Dirty coil/drain pan/humidifier

Check in this order

  1. Fix leaks, dehumidify basement (not exhaust if outdoor air humid), UV on coil/pan, HVAC cleaning, HEPA vacuuming

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Source: General HVAC service practice — verify per model. Written in our own words; check the manual for your exact model.

For licensed technicians. Gas, electrical and refrigerant work must be done by a qualified, licensed person. Shut off power and gas before servicing, never bypass a safety control, and follow the manufacturer’s manual for the exact model; it and local codes always take priority. HVACopedia is not affiliated with any manufacturer; brand and model names only identify the equipment.