Rational iCombi Pro - Error 24: SSR Hot Air

🛑 Critical / Stop Operation
Warning: The information provided here is for educational purposes only. Working with commercial kitchen equipment involves high voltage, gas, and high temperatures. We strongly recommend contacting a certified service technician for any repairs. We are not responsible for any damage or injuries resulting from DIY repair attempts. This information is provided 'as is' without any guarantees of completeness or accuracy.

TLDR

On your iCombi Pro unit, error code 24 indicates a malfunction with the Solid State Relay (SSR) responsible for controlling the hot air heating elements. This critical issue prevents proper temperature regulation in hot air mode and can render the oven unusable. You must inspect the SSR and associated wiring for damage or short circuits to restore functionality.

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Technical Details

Repair Steps:

  1. Safety First:
    Immediately disconnect the iCombi Pro unit from the main power supply. Lock out/tag out procedures are essential. Wait for all components to cool down before proceeding.
  2. Access the Components:
    Carefully remove the rear panel of the iCombi Pro to gain access to the electrical compartment. Locate the main control PCB and the Solid State Relays (SSRs) which are typically mounted on a heatsink. Identify the SSR responsible for the hot air heating elements (consult the wiring diagram if unsure, it’s usually labeled or part of a bank controlling high-power loads).
  3. Visual Inspection of the SSR and Wiring:
    Examine the hot air SSR for any visible signs of damage, such as burn marks, discoloration, bulging, or melted plastic. Check all connected wiring for fraying, loose connections, or heat damage. Pay close attention to the terminals and connections at both the SSR and the hot air heating elements.
  4. Electrical Testing of the SSR:
    • Resistance Check: With the power OFF and wires disconnected, measure the resistance across the load terminals (output) of the SSR. It should be open (infinite resistance). If you read a low resistance, the SSR may be shorted.
    • Control Voltage Check: Reconnect the control wires to the SSR (but keep main power disconnected from heating elements if possible for safety). With the unit powered on (briefly and cautiously, observing safety), measure the DC voltage across the control input terminals of the SSR when hot air heating is commanded. You should see the appropriate control voltage (e.g., 5-32V DC) when heating is active. If control voltage is present but the SSR isn’t switching the load (after main power is reconnected and safely tested), the SSR is likely faulty.
    • Continuity of Heating Elements: Also, check the continuity of the hot air heating elements themselves. An open or shorted heating element can sometimes stress and damage the SSR.
  5. Check for Overheating:
    Inspect the heatsink on which the SSR is mounted. Ensure it is clean and free of dust or debris that could impede heat dissipation. Overheating is a common cause of SSR failure. Ensure thermal paste or pads are correctly applied if replacing.
  6. Replace the SSR:
    If the SSR is confirmed faulty (shorted, open, or not switching despite control voltage), replace it with a genuine RATIONAL replacement SSR with the correct specifications (voltage, current, control voltage). Ensure proper mounting on the heatsink and correct wiring.
  7. Test and Monitor:
    After replacement, carefully reassemble the unit. Restore power and initiate a hot air cooking program. Monitor the unit closely for proper heating element operation, temperature regulation, and absence of the error code.

Common Questions:

Q: What does “SSR hot air” mean on my RATIONAL iCombi Pro?

A: “SSR hot air” (Error 24) on your iCombi Pro indicates a fault with the Solid State Relay that controls the hot air heating elements. This means the oven’s ability to generate or regulate hot air for cooking is compromised.

Q: Can I continue using my iCombi Pro with Error 24?

A: No, it is not recommended to continue operating the iCombi Pro with Error 24. A faulty hot air SSR can lead to improper temperature control, potential overheating, or complete failure of the heating system, posing a safety risk and preventing proper cooking.

Q: What are the primary causes of a hot air SSR failure?

A: Primary causes include electrical overloads, short circuits in the heating elements, high ambient temperatures leading to overheating of the SSR, wear and tear over time, or internal component failure within the relay itself. A thorough electrical diagnosis is required to pinpoint the exact root cause.

When to call a technician

For this error, we recommend calling a certified technician. Do not continue operation or attempt repair yourself.

  • Equipment shows a critical or stop-operation fault.
  • You smell gas, burning, or see smoke or sparks.
  • Error returns after following the steps above.
  • You are not trained to work on this equipment.
  • Warranty or safety could be affected by DIY repair.

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