Mishnah Shabbat

(ד) מעשה שעשו אנשי טבריא והביאו סילון של צונן לתוך אמה של חמין. אמרו להן חכמים: אם בשבת , כחמין שהוחמו בשבת - אסורין ברחיצה ובשתיה, ביום טוב, כחמין שהוחמו ביום טוב - אסורין ברחיצה ומתרין בשתיה. מוליאר הגרוף שותין הימנו בשבת. אנטיכי, אף על פי שגרופה, אין שותין ממנה.

(4) It once happened that the inhabitants of Tiberias ran a pipe of cold water through a channel of hot water. The Sages said to them: If [the cold water is heated] on Shabbat, it is like any water that has been heated on Shabbat and is prohibited for either washing or drinking; [if this water is heated] on a festival, it is like any hot water that has been heated on the festival and is prohibited for washing but permitted for drinking. One may drink from a mulyar [a pot for cooking that has an attached compartment for coal] that has been swept [of coals] on Shabbat. One may not drink from an antichi [a double shelled pot which contains coals in its space] even though it has been swept [of coals].