HUM SNS ERRMunters

Munters HUM SNS ERR Error Code

Error in humidity sensor

Source: hvac/munters/0d9d3440__smart-c__mntr-smart-c-d-iom.pdf

What does Munters HUM SNS ERR mean?

On a Munters Smart C/D climate controller, HUM SNS ERR signals a fault in the humidity sensor. The manual states humidity sensor number 1 is either out of order or disconnected, so the controller cannot read a valid humidity value. The alarm appears on the main screen, shown alternately with the normal display until the problem is resolved.

Symptoms

  • HUM SNS ERR alarm displayed on the main screen
  • Humidity reading is invalid or absent
  • Alarm relay triggers and repeats until the fault is cleared
  • Humidity-driven functions do not operate as expected

Common causes

  • Humidity sensor number 1 is out of order
  • Humidity sensor number 1 is disconnected

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Diagnostic steps

  1. Acknowledge the alarm

    Press OK on the main menu to reset the alarm relay; the manual notes the message continues until the issue is resolved.

  2. Check the humidity sensor connection

    Inspect the humidity sensor wiring for a disconnected lead, a cause given in the manual.

  3. Replace a failed humidity sensor

    If the humidity sensor is out of order, install a working sensor.

  4. Confirm the sensor is installed

    The manual notes the Target Humidity option appears only when a humidity sensor is installed, so verify the sensor is present and wired.

  5. Disable the alarm only if the sensor is removed deliberately

    Per the manual, a deliberately removed sensor's error alarm can be disabled via the Calibration menu.

When to call a professional

The Smart C/D manual cautions not to open the controller box when a hardware problem arises and to contact an authorized electrician. Call a qualified technician if the alarm persists after checking the humidity sensor connection, if you cannot safely access the wiring inside a mains-powered enclosure, or if replacing and recalibrating the sensor is beyond your experience.