Getting the Most from Steam
When baking with a rack oven, in order to get the full benefit of the steam, it is helpful to turn off the oven for 1-3 minutes (depending on oven quality) after the rack has been placed in the oven and the steam injected into the bake chamber.
This will give enough time for the steam to get deposited on the loaves and keep the chamber humid, before the fan dries it out. As a result, the breads will have better cut openings, better volume and better coloration.
Note that if the rack oven has a fan delay option, it could be used instead of shutting down the oven completely (and sometimes forgetting to turn it back on?).