Depending on the website's configuration it may take anywhere from 1 hour to no more than 24 hours to refresh automatically. When at the page with the rate boards you can attach ?refresh=1 to the end of the URL(address) and this will manually refresh that rate board.

For example, if the URL reads <www.yoursite.com/rates.php> (substituting "yoursite.com" with the credit union's particular URL), you can enter the URL as <www.yoursite.com/rates.php?refresh=1>.