98:25 We may not extinguish a fire on yom tov; even to cause it to go out is prohibited. (Rema 514:3 permits one to cause it to go out; Mishnah Brurah 514:23 recommends following the stringent majority position.) Therefore, we may not place a lit candle somewhere that the wind might blow and put it out. This is true even if at the moment the wind isn't blowing. Similarly, we are not permitted to open a door or a window opposite a lit candle.
98:26 It is permitted to cover a fire with a vessel or with ashes that were prepared before yom tov. Even though it's possible (and not inevitable – MB502:10) that the fire will be extinguished by being covered, since one did not intend to put it out – and since this is a form of work that is not needed for its own sake - it is permitted for yom tov needs, specifically for the needs of the same day. To do this by day for needs of the night is prohibited because the night is part of the next day.