Understand the Anti-Cold Air FunctionUpdated 3 days ago

This article explains the Anti-Cold Air function for Vertex Ducted Central Split (DYC-18) systems. 

This function utilizes the T1 (indoor room temperature) and T2 (indoor coil temperature) sensors in the indoor unit to inform the blower whether to turn on or off. The function prevents cold air to blow during Heating mode. 

The function will activate when the following conditions are met: 

• The system is in Heating mode. 
• The SW1-2 DIP switch is set to "Off."
• The T2 sensor detects the temperature is less than 82°F (28°C). 
• The electric heat kit is off. 
• The Y1/Y2 signal is energized when connected with a 24V thermostat. When a manufacturer-supplied RS-485 communicative thermostat is connected, the indoor fan blower is activated by the thermostat. 

The function will deactivate when the following conditions are met:

• The T2 sensor detects the temperature is more than 90°F (32°). 
• The electric heat kit is on.