Carel E13

What does Carel E13 mean?

E13 on Carel ir33 and pCO controllers signals that serial probe S13 has not been updated within the controller's polling timeout. S13 is part of the Carel serial probe network, and when communication fails the controller loses that sensor's temperature reading. Control functions depending on S13 fall back to duty-cycle mode (parameter c4) until communication is restored.

Symptoms

• E13 displayed alternating with temperature on the controller.
• S13-dependent control functions revert to duty-cycle fallback operation.
• Alarm output and buzzer activate.
• The specific zone or circuit monitored by S13 has no live temperature data.

Common causes

• Data cable fault between the controller and S13 probe.
• S13 probe power supply interruption.
• Bus address conflict with another device.
• Failed S13 probe hardware.

Diagnostic steps

1. 01

   Locate and inspect the S13 probe

   Identify the physical location of S13 in the system. Inspect the probe housing, cable, and bus termination for visible damage.

2. 02

   Confirm S13 power supply

   Measure voltage at the S13 supply terminals. Absence of supply voltage indicates a broken power feed that must be traced and repaired.

3. 03

   Verify bus wiring continuity

   With the system de-energized, use a multimeter to confirm both RS-485 data lines read less than 5 Ω from controller to S13 probe.

4. 04

   Confirm unique bus address for S13

   Check the S13 address setting and compare it against all other probes on the bus. Reconfigure if a duplicate address is found.

5. 05

   Replace probe if all wiring is confirmed good

   If the bus and power supply are intact and E13 persists, replace the S13 probe with a compatible Carel serial probe unit.

When to call a professional

Escalate to a qualified Carel technician if multiple serial probes are faulting simultaneously, which indicates a bus-level failure such as a shorted data line or a controller communication board defect rather than individual probe failures. These faults require specialized diagnostic tools and component replacement skills.