Munters T3 SNS ERR

What does Munters T3 SNS ERR mean?

On a Munters Smart C/D climate controller, T3 SNS ERR means a fault has been detected in temperature sensor 3. The manual states this sensor is either out of order, disconnected, or shorted, so the controller cannot obtain a valid temperature from that input. The alarm shows on the main screen, alternating with the normal display.

Symptoms

• T3 SNS ERR alarm shown on the main screen
• Temperature from sensor 3 reads as invalid or missing
• Alarm relay activates and the alarm repeats until cleared
• Control functions relying on sensor 3 behave abnormally

Common causes

• Temperature sensor 3 is out of order
• Temperature sensor 3 is disconnected
• Temperature sensor 3 wiring is shorted

Diagnostic steps

1. 01

   Acknowledge the alarm

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

2. 02

   Check the sensor 3 connection

   Inspect temperature sensor 3 wiring for a disconnected lead, a cause noted in the manual.

3. 03

   Inspect the wiring for a short

   Check the sensor 3 cable for a short circuit, listed as a possible reason in the manual.

4. 04

   Replace a failed sensor

   If sensor 3 is out of order, fit a working temperature sensor on that input.

5. 05

   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 that if a hardware problem arises you should not open the box and should contact an authorized electrician. Call a qualified technician if the alarm remains after checking the connection, if you are not equipped to work safely inside a mains-powered controller, or if sensor replacement and recalibration exceed your experience.