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120 volts can cause serious injury from electric shock. Disconnect electrical power to the HVAC system before proceeding.
Ensure furnace blower runs long enough after heat call to prevent over-temperature.
Mount the control to the return duct and the outdoor sensor as shown on pages 6-9 if humidity limits are important.
Connect the control to the HVAC equipment according to Figure 1.
Connect the control to the HVAC equipment according to Figure 2.
Connect the control to the 8140NC ventilator according to Figure 3.
Connect the control to the Model 6506 damper according to Figure 4.
Verify all ventilation system components and wiring function correctly.
Register your Aprilaire product online or by mail to activate warranty.
120 volts can cause serious injury from electric shock. Disconnect electrical power to the HVAC system before proceeding.
Ensure furnace blower runs long enough after heat call to prevent over-temperature.
Mount the control to the return duct and the outdoor sensor as shown on pages 6-9 if humidity limits are important.
Connect the control to the HVAC equipment according to Figure 1.
Connect the control to the HVAC equipment according to Figure 2.
Connect the control to the 8140NC ventilator according to Figure 3.
Connect the control to the Model 6506 damper according to Figure 4.
Verify all ventilation system components and wiring function correctly.
Register your Aprilaire product online or by mail to activate warranty.
The Aprilaire Model 8120X Digital Ventilation Controller is a sophisticated device designed to manage and optimize fresh air ventilation in residential HVAC systems. Its primary function is to ensure a healthy indoor environment by providing controlled introduction of outdoor air, while also considering factors like temperature and humidity to maintain comfort and energy efficiency.
The controller operates by integrating with the home's existing HVAC system, specifically controlling a fresh air ventilator or a damper. It continuously monitors indoor and outdoor conditions, making intelligent decisions about when and how much fresh air to bring into the home. This digital controller aims to meet ASHRAE 62.2-2010 ventilation standards, which specify minimum ventilation rates for residential buildings to dilute indoor pollutants and maintain air quality.
The core of its operation revolves around a user-defined ventilation schedule, which can be set in minutes per hour. The controller can operate in two main modes: "Code" and "Comfort."
In "Code" mode, the controller prioritizes meeting the ASHRAE 62.2-2010 ventilation requirements. It will turn on ventilation during heating, cooling, or fan calls for a set number of minutes within a one-hour cycle. If the outdoor temperature exceeds a high temperature ventilation limit or falls below a low temperature ventilation limit, ventilation will be restricted or adjusted. For instance, if the outdoor air is too hot or too cold, the controller might only ventilate during a heat call (if too cold) or restrict ventilation during a cool or fan call (if too hot). If the HVAC equipment doesn't run long enough to meet the required ventilation time within an hour, the controller will activate ventilation independently, provided outdoor air temperatures are within the set limits. It can also engage the HVAC system blower if wired and configured to do so. If outdoor temperature limits are continuously exceeded, the controller intelligently adjusts its cycle period from one hour to four, then eight, twelve, and finally twenty-four hours, increasing the total ventilation time to compensate for reduced effectiveness during limited operation. This ensures that the cumulative ventilation requirements are met even under challenging outdoor conditions.
In "Comfort" mode, the controller adds indoor relative humidity (RH) limits to its ventilation logic. This means that in addition to outdoor temperature limits, ventilation will only occur if the indoor RH is within a user-defined high and low limit. If the indoor RH exceeds the high limit or drops below the low limit, ventilation will be suspended to prevent discomfort or potential issues like excessive dryness or condensation. Unlike "Code" mode, any ventilation missed due to these humidity limits is not made up, as the primary goal is to maintain indoor comfort.
The controller's decision-making process is influenced by several user-configurable settings, including the number of bedrooms, square footage of the house, and the measured outdoor airflow delivered by the ventilation system. These parameters are used to calculate the "Required Continuous CFM" (Cubic Feet per Minute), which is then used to determine the appropriate ventilation time in minutes per hour.
The Aprilaire 8120X offers a user-friendly interface with a digital display and intuitive buttons for setup and operation.
The manual does not explicitly detail ongoing maintenance features for the controller itself, as it is primarily an electronic control device. However, its design and operation implicitly contribute to the maintenance of the overall ventilation system and indoor air quality:
In summary, the Aprilaire Model 8120X Digital Ventilation Controller is a comprehensive solution for managing residential fresh air ventilation, offering intelligent control, user-friendly setup, and robust operational modes to ensure both healthy indoor air quality and comfort while optimizing energy use.
General| Model | 8120X |
|---|---|
| Category | Controller |
| Power Supply | 24 VAC |
| Installation | Wall-mounted |
| Outdoor Temperature Sensor | Optional |
| Display | Digital |
| Compatibility | Aprilaire Humidifiers |
| Dimensions | 4.5" x 1.25" |
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