I made my whole-home humidifier slightly less terrifying

Quick Overview

The speaker successfully installed a newer Aprilaire Model 60 digital humidifier controller in place of an older analog controller, wiring it to control both the humidifier and the furnace blower fan simultaneously, which solved the issue of the old controller causing water leaks by running continuously during heating cycles.

Key Points: The existing Aprilaire Model 700M humidifier controller was replaced with a newer Model 60 Automatic Digital Humidifier Control to solve recurring water leaking issues. The original analog setup required the humidifier to run only when the furnace was actively heating, but the faulty analog controller caused the humidifier to run continuously during heating calls, leading to excessive water waste and potential damage. The new digital Model 60 controller requires wiring to both the humidifier's water valve (HUM terminals) and the furnace control board's fan terminal (G) to ensure the blower runs whenever the humidifier is called upon. The speaker used a 50-foot fish tape to run the necessary external temperature sensor wire through the furnace intake pipe, which was an awkward path requiring careful maneuvering. The outdoor temperature sensor wire was successfully connected to the new digital controller's appropriate terminals, allowing it to adjust the target humidity based on outdoor temperature as per Table 2 in the manual. After wiring and testing, the new digital controller correctly activated the humidifier when humidity was low and correctly shut it off when the humidity target was met, even when the furnace was running. The speaker noted that the old analog controller was likely malfunctioning because it failed to stop the humidifier when the furnace blower was not running during heating cycles, leading to condensation and wasted water.

Context: The video details the process of upgrading an older Aprilaire whole-home bypass humidifier controller (likely a Model 700 series) to a newer, more advanced Aprilaire Model 60 Automatic Digital Humidifier Control. The motivation was to fix a persistent issue where the old analog controller caused the humidifier to run excessively during furnace heating calls, leading to water waste and condensation issues. The upgrade required running an external temperature sensor wire through the furnace ductwork and correctly wiring the new digital controller to both the humidifier's water valve and the furnace control board's fan signal wire (G terminal).