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Dedicated Rational oven support

Rational Combi Oven Fault Finder

Work through these safe operator checks and tell us what the display is showing. Your answers will be added to the engineer request.

Stop and switch the oven off if there is smoke, a burning smell, sparking or a significant water leak. Do not remove covers, reach into a hot cabinet or attempt an internal repair. Call us on 01202 377205 if you are unsure.

Display message guide

Common Rational oven error codes

Codes and permitted operation vary by model. Record the complete message exactly as shown. These notes explain safe operator checks only; they do not replace a qualified diagnosis.

OPEn H2O

The oven is not receiving enough water. Check that the normal water tap is open and the visible inlet hose is not kinked. Book an engineer if the message remains.

Service 10, 11, 12 or 14

A steam-generator or water-system function needs attention. Note the exact code. Some models may allow limited cooking, but the oven should be inspected.

Service 20, 21 or 23

A control or operating function has failed. Follow the message on screen, stop the oven if instructed and arrange an engineer.

Service 29

Check the user-accessible air filter and make sure another heat source is not overheating the control area. If the message remains, book an engineer.

Service 31

The core-temperature probe is faulty. Do not use a visibly damaged probe. Record the code and arrange repair.

Service 32 or 33 — gas ovens

Gas ignition or combustion needs attention. Stop the oven, close the appliance gas valve if safe and book an engineer. If you smell gas, follow your gas-emergency procedure.

Service 40–44

The cleaning or Care system has not completed correctly. Follow the on-screen instructions. Do not add extra chemicals or open the door during an active cleaning cycle.

Service 110 or 120

A cleaning, pump or steam-generator water fault requires service. Allow any automatic abort or rinse process to finish, then arrange an engineer.

1. Is the display illuminated?

Check the oven’s normal power control and that the wall isolator has not been switched off.

2. Is the oven door fully closed?

Check that trays, food or debris are not preventing closure and that the seal is seated. Do not force a damaged door or catch.

3. Is the water supply on?

Check the visible supply valve is open and the inlet hose is not trapped or kinked.

4. Is the visible cabinet drain clear?

When the oven is cool, remove only loose food debris that can be reached safely. Do not dismantle the drain or pipework.

5. Are the oven’s ventilation openings clear?

Move boxes, cloths and other items away from visible vents and allow the oven to cool if it has overheated.

6. Is the display showing an error or service message?

Write down the exact wording or code. If possible, also note the model and serial number from the rating plate without moving the oven.

7. If safe, has the oven been restarted once?

Only if there is no smoke, smell, sparking or leak: switch it off normally, wait 30 seconds, then switch it on once. Do not keep resetting a recurring fault.

8. Is there smoke, a burning smell, sparking or a significant leak?

If yes, stop using the oven and isolate it only where it is safe to do so.

If these checks have not solved the fault, send the results to CEMCO and book a Rational-trained engineer.

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