Carrier Furnace Error Code 23

Error code 23 on a Carrier furnace means the pressure switch did not open when the control board expected it to during the heating cycle. The pressure switch is a safety component that monitors airflow through the venting system and should cycle open and closed at specific points during furnace operation. When it stays closed instead of opening, the furnace shuts down and logs this code. The most common causes are blocked pressure tubing or a pressure switch that is mechanically stuck closed.

No, you should not attempt to force the furnace to run continuously while code 23 is active. The pressure switch system exists to verify that combustion gases are being safely vented before and after each firing cycle. A stuck or faulty pressure switch means the furnace cannot confirm safe venting conditions, and bypassing or ignoring this fault creates a risk of incomplete combustion or carbon monoxide buildup. Have the issue diagnosed and repaired before returning the furnace to regular use.

Repair costs depend on the root cause. Clearing a blocked pressure tube or condensate drain is inexpensive and may only involve a service call fee, typically in the range of $75 to $150. Replacing a faulty pressure switch generally costs between $100 and $250 including parts and labor. If the inducer motor or housing needs replacement, costs can range from $300 to $700 or more depending on the model and labor rates in your area.

Some causes of code 23 are accessible to a knowledgeable DIYer. You can inspect the pressure switch tubing for kinks, blockages, or condensate buildup and clear them without special tools. Checking and clearing a clogged condensate drain is also a reasonable DIY task. However, testing and replacing the pressure switch, inducer motor, or housing components typically requires a multimeter and comfort working inside the furnace cabinet, and in some cases a licensed HVAC technician is the safer choice.

Resetting the furnace by cycling the power may temporarily clear the fault display, but the code will return if the underlying cause has not been corrected. The control board will detect the same pressure switch behavior on the next heating cycle and log the fault again. A reset is useful for confirming whether the issue is intermittent, but it is not a repair and should not be relied on as a solution.