At the end of Dragon Ball, when Goku and Chi Chi were questing to find the Bansho Fan to put out the fire trapping the Ox King, it seems as if they could have used the Dragon Balls to do it quickly. More than one year had passed since their previous usage and, as far as I could tell, the balls were not scattered after wishing Krillin and the others back to life (they remained on the ground at the Kame House after the wish).
So, it seems like they could have quickly made a wish to stop the flames and restore the castle. Why did they not do so? I did not read the manga, I only watched the anime. Was there a specific reason that either I missed, or that was perhaps stated in the manga, or was it simply a plot device to fill the last few episodes of the series?