Aprilaire
SPECIFICATION SHEET VENTILATION SYSTEM MODEL 8126A
PRODUCT SPECIFICATIONS
| Overall Dimensions | 4-1/4" H x 6" W x 1-3/4" D |
| Duct Opening Dimensions (for humidity sensor) | 3/4" Diameter Hole |
| Input Power for the Control (from the HVAC system transformer) | 24 VAC, 1 VA |
| Damper Outputs (A/A) | 1A max. at 24 VAC |
| Outdoor Temperature Sensor Inputs | Thermistor (provided) |
| Damper Transformer (provided) | 24 VAC, 10 VA |
| Cycle Time | 1 hour |
| Ventilation Time Dial Setting (minutes per cycle) | Off, 0-60, Test/Reset |
Diagram: Aprilaire Digital Ventilation Controller
The Aprilaire Digital Ventilation Controller features a dial labeled 'Minutes Per Hour' with settings from 0 to 60, an 'Active Ventilation' indicator light, and two buttons: 'Test' and 'Reset'.
PRINCIPLE OF OPERATION
The Aprilaire 8126A ventilation system brings in fresh air and activates the HVAC fan to cycle the fresh air throughout the home. The controller is designed to meet the ASHRAE 62.2-2010 standard for ventilation. The ventilation mode selection allows for time only operation or for temperature and humidity limits to be applied to the incoming air.
SET OF OPERATION
Every hour, the Model 8126A ventilation system will open the ventilation damper and turn on the HVAC system blower for the amount of time set on the Ventilation Time dial. Ventilation will occur first, when the HVAC system calls for either heating (W input), cooling, or continuous fan (G input). If the HVAC system is not on for the amount of time set on the Ventilation Time dial, the controller will open the damper and turn on the HVAC system blower at the end of the one hour cycle time in order to meet the set Ventilation Time. For example, assuming the Ventilation Time is set to 20 minutes per hour and the heating or cooling was on for 10 minutes during that hour, ventilation would be provided during that time, and the ventilation controller would open the damper and turn on the HVAC system blower for the last 10 minutes of the hour to meet the 20 minute ventilation time.
High and Low temperature limits are available in Modes B, C, D, to prevent outdoor air that is too hot or too cold from being delivered to the home. If the outdoor temperature rises above the High Limit or drops below the Low Limit, ventilation will not occur. If the outdoor temperature drops below the Heat Only Limit, ventilation will be allowed only when the HVAC system is calling for heat.
A high indoor RH limit is available when in Modes B, C, D, to prevent potentially humid outdoor air from being delivered to an already humid home. If the indoor RH is above the Indoor RH Limit, and the outdoor temperature is above the corresponding limit, ventilation will not occur.
Both the temperature and RH limits are overridden when in Mode A.
Diagram: Typical Attic Installation
A diagram illustrating a typical attic installation. It shows fresh air entering through an intake hood, passing through a motorized damper and filter, then through a furnace/air handler. A ventilation controller is shown, and airflow is indicated towards the living space.
Diagram: Typical Basement Installation
A diagram illustrating a typical basement installation. It depicts fresh air intake, a motorized damper, filter, furnace/air handler, and ventilation controller, with airflow directed to the home.
MODE SELECTION
| Position | Description | Chart Description |
|---|---|---|
| A (Time Only) | Timer controlled ventilation (No temperature or humidity limits) | This setting can be calculated with ASHRAE 62.2-2010 standards. Temperature and humidity sensors are ignored. |
| B (Default) | Timer controlled ventilation with humidity and temperature limits |
Chart Axes: Y-axis: Outdoor Temperature (F) [Key points: 100°, 50°, 20°, 0°]. X-axis: Indoor Relative Humidity (%) [Key points: 15%, 25%, 35%, 45%, 55%, 65%]. Regions:
|
| C (Cold Climate) | Timer controlled ventilation with humidity and temperature limits |
Chart Axes: Y-axis: Outdoor Temperature (F) [Key points: 100°, 50°, 0°]. X-axis: Indoor Relative Humidity (%) [Key points: 15%, 25%, 35%, 45%, 55%, 65%]. Regions:
|
| D (Warm Climate) | Timer controlled ventilation with humidity and temperature limits |
Chart Axes: Y-axis: Outdoor Temperature (F) [Key points: 90°, 50°, 40°, 0°]. X-axis: Indoor Relative Humidity (%) [Key points: 15%, 25%, 35%, 45%, 55%, 65%]. Regions:
|
