Rational Combi Oven Error Code Service 35: UltraVent Disconnected

What does Rational error code Service 35 mean?

UltraVent is the optional condensing hood on the oven, and it talks to the control over a bus connection. When the control cannot get that signal, it concludes the hood is disconnected and shows Service 35. The oven can still cook in many cases, but steam handling is affected, because the hood is part of how steam leaves the cabinet. The cause is often as simple as an unplugged cord. The maker's list names the power plug and outlet for the UltraVent, the cable between the UltraVent and the oven, the UltraVent switch and internal fuse, and the bus connection at the oven. The owner's manual lists an operator step for this message, and that step is to plug the UltraVent in and push the plug fully home. After that the checks move to the outlet, the breaker and the cable. The hood housing holds hot steam parts and live wiring, so the cover stays on, and a failed internal fuse or switch is a technician job.

Affected models and control systems

This applies to the Rational SelfCookingCenter whitefficiency family with the optional UltraVent hood, per the Original operating instructions. Ovens without the hood do not show this message.

Code numbers and their meaning can change between control generations. We match the full model and control before acting on a code.

What you may notice

• Service 35 on the screen
• The UltraVent not running
• Steam escaping into the kitchen
• Cooking possible but steam handling affected

Possible causes

Listed in Rational's documentation

• UltraVent power plug or outlet
• Cable between the UltraVent and the oven
• UltraVent switch or internal fuse
• Bus connection at the oven

Other likely causes — what usually sits behind error code Service 35 on this control. A technician confirms which one it is before any part is replaced.

• Plug pulled partly out when the oven was cleaned or moved
• Breaker tripped on the outlet circuit
• Cable pinched where the hood connects to the oven

Safe checks before calling for service

How a technician diagnoses error code Service 35

1. Read the message and confirm the oven has the UltraVent.
2. Test the outlet and the circuit.
3. Inspect the cable for damage along its run.
4. Check the UltraVent switch and internal fuse.
5. Check the bus connection at the oven.
6. Replace the failed part and confirm the message clears and the hood runs.

How error code Service 35 differs from similar codes

Service 35 is the UltraVent bus signal. Service 34.x covers motors and ignition modules inside the oven.

Technical reference

Document

RATIONAL SelfCookingCenter Original operating instructions

Models / control

SelfCookingCenter whitefficiency (SCC_WE) family

Section

Fault messages table, printed pp. 188-191 (PDF pp. 188-191 of 201; footer reads n / 198)

Checked

October 2026

We use the maker's document to read the code and do not reproduce it. Always confirm the complete model and control before applying these steps.