Chazara, On Shabbos, it is permissible to place onto a pot of hot water, a dish of food that is already fully cooked such as Panades or the like, in order to warm it, since he is not cooking in a usual manner. However it is definitely forbidden to place (food) under cloths that cover a water kettle. RAMA: similarly it is forbidden to place (food) on a Kirah even if it is Gerufa and Ketuma, as the sages only permitted Chazora (but not placing a pot for the first time), as has been explained above. Some (authorities) permit placing (a pot of food) into a Tanur used for baking on Erev Shabbos, when no food was left warming in it (it was merely used for baking on Erev Shabbos), only a small amount of heat remains and there need be no concern that this will cause it (the pot) to be cooked – provided (the food) has not cooled completely. Some, however, are stringent here, and (hold that) if the heat of the Tanur is so intense that it is of Yad soledes bo, it is forbidden. See below Siman 318. One may not tell a non-Jew to do anything that is forbidden to do himself. It is therefore forbidden to tell a non-Jew to heat up the pot (of food) that has cooled. If one does so, it is forbidden to eat it even cold. [Beis Yosef and the Teshuvos HaRashba] However, if the food has not cooled below the temperature at which it is edible, it may be eaten if the non-Jew heats it up. For this reason it is common practice to have non-Jews remove pots of food from ovens in which they have been stored to retain their heat, and place them next to or on top of a heating stove, and then have the (non-Jewish) maidservant light the stove, whereupon the food will become boiling hot once again. However it is forbidden to do this through a Jew. (Terumas HaDeshen) If, however, the pots are still hot they may be placed next to the heating stove. The reason is that, as has been explained, our ovens have a status of a Kirah, and placing it next to a Kirah, which is not Garuf Ve’katum, has the same law as placing directly on top of it when it is Garuf Ve’katum (which is permitted). It has already been stated that the customary practice is to be lenient (and permit) to do Chazora [returning a pot to the stove] even if the pot has been placed on the ground. Similarly, placing (a pot) next to an oven, which is not Garuf Ve’katum (is permitted) if the food is still hot and fully cooked. It is a widespread, accepted practice to permit this. See below Siman 318.