warning Aprilaire

Error Code 3 blinks

Overheating warning, likely due to blocked ventilation or fan failure.

? What Causes This

Blockage around humidifier vents preventing adequate cooling of equipment core components.

How to Fix It

Turn system off to allow it cool; remove any obstructive debris from around vents. Proceed with caution if error persists by contacting service team.

Source: page 27 of the official manual

From the manual

Manual page 27 — Aprilaire error 3 blinks

This error code appears in:

Aprilaire 800