⚠
warning Honeywell
Error Code 186
Clean ventilator core — the ventilator core needs to be cleaned.
? What Causes This
Ventilator core has accumulated dust or debris.
✓ How to Fix It
Clean the ventilator core or contact your heating or cooling professional. Reset the timer by touching Dismiss on the thermostat screen after cleaning.
Source: page 28 of the official manual
From the manual
