The AprilAire 720 Humidifier is a whole-home humidification system designed to integrate with a home's HVAC system to maintain optimal indoor humidity levels. This manual provides detailed wiring instructions for various applications, showcasing the versatility and compatibility of the system with different control methods and furnace setups. The core components of the system include the humidifier unit itself, which is typically installed on the supply or return plenum of the furnace, and a control device, such as the Model 60 Automatic Humidifier Control or a Model 4655 Manual Humidifier Control.
Function Description:
The primary function of the AprilAire 720 Humidifier is to add moisture to the air in a home, combating the dryness often experienced during colder months or in arid climates. By maintaining a relative humidity (RH) level between 35% and 45%, the system helps to alleviate common issues associated with dry air, such as dry skin, irritated nasal passages, static electricity, and damage to wood furnishings. The humidifier operates by evaporating water into the airstream of the HVAC system, which is then distributed throughout the home.
The system can be controlled either automatically or manually. The Model 60 Automatic Humidifier Control is a sophisticated device that continuously monitors both indoor humidity and outdoor temperature to automatically adjust the humidifier's output. This intelligent control prevents over-humidification, which can lead to condensation on windows and other surfaces, while ensuring consistent comfort. It features a digital display showing indoor humidity and includes indicators for service reminders (Call Dealer for Service, Change Water Panel) and system status (Humidifier On). The Model 4655 Manual Humidifier Control, on the other hand, allows users to set a desired humidity level based on outdoor temperature, providing a more hands-on approach to humidity management.
Important Technical Specifications:
While specific technical specifications like water panel type, evaporation rate, or bypass duct size are not explicitly detailed in the provided images, the wiring diagrams offer insights into the electrical requirements and control mechanisms.
- Power Supply: The humidifier system typically requires a 120 VAC power source for the humidifier unit itself. The control devices (Model 60 or Model 4655) and associated relays often operate on a 24 VAC low-voltage circuit. A 24 VAC 10 VA (Volt-Ampere) transformer is frequently supplied with the system to convert the higher voltage to the required low voltage for the controls.
- Control Voltage: The control circuits, including the HUM (Humidifier) and EAC (Electronic Air Cleaner) terminals, operate at 24 VAC. It's crucial to note that EAC terminals, if used, may be 120 VAC and must be reduced to 24 VAC before connecting to the humidifier or humidistat.
- Transformer Requirements: When a separate transformer is used for the controls (e.g., for EAC wiring), it must be a minimum of 24 VAC 10 VA.
- Compatibility: The system is designed to integrate with standard furnace and thermostat wiring, utilizing common terminals such as R (24 VAC hot), C (24 VAC common), G (fan), W (heat), and Y (cooling).
Usage Features:
- Automatic Operation (Model 60): The Model 60 control offers "set-it-and-forget-it" convenience. Users simply set their desired humidity level, and the control automatically adjusts output based on real-time conditions. It includes a "Test/Reset" button for diagnostics and system checks. The "Blower Activation" switch allows for continuous fan operation or activation only when the furnace blower is running.
- Manual Operation (Model 4655): The Model 4655 control features a dial that allows users to select a desired humidity percentage, often with recommended settings based on outdoor temperature to prevent condensation.
- Outdoor Temperature Sensor: For automatic mode (Model 60), an outdoor temperature sensor is crucial. This sensor is installed on the north, east, or west side of the home, above the expected snow line, to provide accurate outdoor temperature readings to the control, enabling it to prevent over-humidification.
- Blower Activation Options: The humidifier can be wired to activate only when the furnace blower is running (standard wiring) or, with additional relays, to activate the blower specifically for humidification, even without a call for heat or cool.
- Flexible Wiring Applications: The manual illustrates several wiring configurations, demonstrating the system's adaptability:
- Model 60 Standard Wiring: Connects the Model 60 control to the furnace and a continuously powered 24 VAC transformer.
- Model 4655 Wired to HUM Terminal: Connects the manual control to the furnace's HUM terminals, which typically activate only on heat calls.
- Model 4655 Wired to EAC Using Included Transformer: Connects the manual control to the furnace's EAC terminals, which activate on any fan call, using a supplied transformer to step down voltage if necessary.
- Model 4655 with Current Sensing Relay (Model 50): Utilizes a Model 50 current sensing relay (sold separately) to detect when the furnace blower motor is running, ensuring the humidifier operates only when air is flowing. This is useful when the humidifier needs to be tied into the blower motor's power circuit.
- Model 4655 with Blower Activation Relay (AprilAire 4851): Employs an AprilAire 4851 relay (sold separately) to activate the furnace blower specifically for humidification, even if there isn't a call for heat or cool, providing more independent control over humidification.
- Model 4655 with Air Flow Proving Switch (AprilAire 4592): Integrates an AprilAire 4592 air flow proving switch (sold separately) to ensure the humidifier only operates when there is actual airflow through the ductwork, preventing operation when the fan is off.
Maintenance Features:
- Water Panel Indicator: The Model 60 Automatic Humidifier Control includes a "Change Water Panel" indicator, reminding users when it's time to replace the humidifier's water panel (evaporator pad). Regular replacement of the water panel is crucial for efficient and hygienic operation.
- Service Required Indicator: The Model 60 also features a "Call Dealer for Service" indicator, alerting users to potential issues that may require professional attention.
- Easy Access to Terminals: The controls are designed with a removable knob and cover to reveal the wiring terminals, simplifying installation and troubleshooting.
In summary, the AprilAire 720 Humidifier system offers a comprehensive solution for whole-home humidification, emphasizing ease of installation, flexible control options, and intelligent operation to maintain a healthy and comfortable indoor environment. Its modular design, with various control and relay options, allows for tailored integration into diverse HVAC systems and user preferences.
Need help?
General
To Next Page
