Replaced the Honeywell prestige thermostat under warranty. Reconnected and programmed the thermostat to the specifications for the system. Found the air to be whistling around the Aprilaire 600 humidifier when the basement zone only is calling for heat. Adjusted the bypass damper to open more as well as caulked around the humidifier to seal it to the duct. Thank you for choosing Black-Haak Heating and Electric. Please take a moment to fill out our online survey.