Quick answer: Run a combi oven’s automatic clean cycle at the end of each day with the manufacturer’s cleaner and rinse tabs, and descale the steam generator on a schedule set by your water hardness. Skip either one and grease and lime scale build up until the oven cooks unevenly.
Most modern combi ovens clean themselves. Units like the Rational iCombi, Convotherm, and Alto-Shaam run an automatic wash program that you start at close, usually overnight, using the maker’s own cleaner and rinse agents, whether cartridge tabs or liquid. Use only the OEM-approved chemicals: the wrong cleaner voids warranties and pits the stainless. What gets skipped is the steam side, which needs descaling on its own schedule.
Descale the steam generator
A combi is only as good as its steam, and hard water is what degrades it. Lime scale coats the boiler or the steam element and starves the oven of steam long before it quits, so descaling keeps the oven cooking evenly and skipping it is how combis lose their steam. Modern units track it and prompt a descale, and boiler models are the most sensitive. Water hardness sets the interval, which is why a water filter or softener costs less than the descaling and downtime it prevents.
What the auto-clean does not reach
The cycle scrubs the cavity. The rest of the machine is on you, on a regular basis:
- Wipe the door gasket and check it seals; a leaking gasket wastes heat and steam.
- Pull the fan guard and clean the fan area behind it, where grease collects.
- Clean the glass door interior with a non-abrasive cleaner.
- Clear the drain so wash water and condensate run out freely.
When to call a technician
If the oven cooks unevenly, loses steam, or throws a cleaning or descale fault right after a proper clean, the steam generator, a valve, or a humidity sensor needs a look. Those are the failures a nightly wash cycle cannot fix.
A combi run hard without descaling usually needs just one service visit to get steady steam back. ProToCall services commercial combi and convection ovens down to the steam generator. Call 866-297-5082 or schedule restaurant equipment repair and maintenance.
If the heat itself is uneven, see why a commercial oven is not heating evenly.
For a flat-top on the same line, see how to clean and season a commercial griddle.