!!
critical Aprilaire
Error Code LED flashes red
Service required due to high mineral deposits or faulty operation.
? What Causes This
Mineral accumulation in the steam canister impeding electrical conductivity, leading to nominal current not being reached.
✓ How to Fix It
Rinse clean water through humidifier; replace canister if needed. Check amperage settings and power supply configuration.
Source: page 27 of the official manual
From the manual
This error code appears in:
Aprilaire 800