Whole-home Carrier humidifier control shows H1 and humidifier does not operate.

Safety first: Turn off power to the furnace/air handler at the service switch or breaker before working on the humidifier control wiring.

Steps:

• 1. Locate outdoor sensor: Carrier whole-home humidifiers often use an outdoor temperature sensor wired to the humidifier control or Infinity/Edge thermostat. Find the sensor on the exterior wall and trace its two-conductor cable.
• 2. Inspect wiring: Look for cuts, staples through the cable, or corrosion at the sensor and control terminals.
• 3. Test sensor: Disconnect the sensor leads at the control and measure resistance with a multimeter. Compare to Carrier’s temperature/resistance chart. If reading is open or shorted, replace the sensor.
• 4. Verify connections: Ensure the sensor wires are landed on the correct terminals at the humidifier control or thermostat and are firmly tightened.
• 5. Replace sensor or control: If wiring is intact and the sensor is out of spec, replace the outdoor sensor. If the sensor is good but H1 persists, the humidifier control board may be faulty.