Carrier Air Handler Blowing Cold Air? Heat Pump Dip Switch Settings Explained

Is your heating system blowing cold air on you right before the heat actually kicks in? In this service call, we troubleshoot a customer complaint about "cold drafts" coming from their vents during start-up.

Upon arrival, I immediately noticed that the blower motor was ramping up instantly when the thermostat called for heat. This is a classic sign of a configuration error. The air handler was set up for "Straight A/C" mode instead of "Heat Pump" mode. In A/C mode, the fan turns on immediately; in Heat Pump mode, there should be a delay to allow the coil to warm up first!

In this video, I show you:

• The initial diagnosis: Recognizing the lack of blower delay.
• Accessing the Carrier/Bryant ECM control board.
• How to adjust Dip Switches for the correct tonnage and Heat Pump mode.
• Setting the "On-Delay" to 30 seconds to eliminate cold drafts.
• Verifying the fix with a proper ramp-up sequence.

Timestamps:
0:00 - The Complaint: Cold drafts & instant airflow
0:50 - Testing the system response
1:56 - Locating the air handler in the attic
2:45 - Inspecting the control board configuration
3:30 - The Problem: System set to "AC" instead of "HP"
4:00 - Adjusting Dip Switches (Kw, Tonnage, & Delay)
4:57 - Verification: Testing the new 30-second delay

Tools Used:
• Emerson Sensi Thermostat App
• Milwaukee M12 Drill
• Klein Tools


About Nelson's HVAC:
Serving the Northern Virginia area with honesty and technical expertise. We don't just change parts; we solve problems.
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