Carrier HVAC Error Code 23: How to Fix It

Q: What does Carrier error code 23 mean?

It means the pressure switch is not closing, which is required for the furnace to operate safely. Common causes include blocked vent, faulty pressure switch, or failed inducer motor.

Q: Can I bypass the pressure switch to run the furnace?

No, never bypass a pressure switch. It is a safety device that prevents operation if there is a vent blockage or insufficient draft, which could lead to carbon monoxide poisoning.

Q: How do I test a pressure switch with a multimeter?

Disconnect wires and set the multimeter to resistance (ohms). With no air pressure, the switch should be open (infinite resistance). Apply suction with a tube (or run inducer) and the switch should close (near zero ohms).

Q: Where is the pressure switch located on a Carrier HVAC?

It is usually mounted near the inducer motor blower housing, connected by a small rubber tube. On some models, it may be inside the blower compartment.

Q: What tools do I need to fix error 23?

A multimeter to test the switch and inducer motor, a screwdriver to remove panels, and cleaning tools for the vent. You may need replacement parts like a new pressure switch or inducer motor.

Abstract

Carrier HVAC error code 23 means the pressure switch is not closing as expected, often due to a blocked vent, faulty switch, or draft inducer issue. This can prevent your furnace or boiler from starting. We'll walk you through common fixes.