The Aprilaire 8126A ventilation system will bring in fresh air and activate 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), or 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 emperature 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 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.
