Convotherm E99

What does Convotherm E99 mean?

Convotherm shows E99 — Communication error - connection lost — on the maxx, maxx pro, mini combi oven range. This is a collective code: it can flag a lost connection, an SD-card error, an invalid system date, or a UI/SIB software mismatch. The manual lists these reasons: Power supply was faulty; Buffer battery for the electronics was drained; Date value is invalid after replacing the buffer battery. The control flags the fault and holds the affected function until the message is cleared.

Symptoms

• Display shows error code E99 (Communication error - connection lost)
• The affected function is interrupted until the fault is cleared

Common causes

• Power supply was faulty
• Buffer battery for the electronics was drained
• Date value is invalid after replacing the buffer battery

Diagnostic steps

1. 01

   Restart the appliance

   Switch off the appliance Re-start the appliance after 10 sec. If the error still appears, contact the responsible service partner (make a note of the message on the display)

2. 02

   Reset the date/time and recharge the battery

   Acknowledge the error message Then set the current date and time Work with the appliance for a while (so that the battery can be recharged) If the error still appears, contact the responsible service partner (make a note of the message on the display)

3. 03

   Update software and set the date on the UI board

   Carry out a software update to the latest software Set the current date on the UI board Open the date setting by pressing and holding the START button and enter the current date

When to call a professional

The manual routes E99 (Communication error - connection lost) to the responsible Convotherm service partner. Note the exact message on the display, stop using the affected function, and call a qualified technician — board, sensor and electrical diagnosis on a combi oven involves live components.