South Street Diner owner Sol Sidell was overwhelmed during the recent screening of the Long Haul Films documentary about his business. He didn’t know the filmmakers before they approached him about filming in the restaurant, and he wasn’t sure what they would come up with. In the end, he was pleased - and touched. “Sometimes when you’re in the adrenaline high you forget how important the diner is to customers and what it means to them,’’ said Sidell (pictured), who took over the 24-hour restaurant 14 years ago when he was 26. “When you’re working there on an every-single-day basis, you forget. . . . They’re a very special group of customers.’’ Melissa and Tom Dowler, who run Long Haul Films, showed their project, “24 Hours at the South Street Diner,’’ to Sidell and friends at the diner this month and are now submitting it to festivals for consideration. The movie follows the business for an entire day and includes history about the eatery and interviews with former owners. “We’ve submitted the film to 10 or so film festivals,’’ Tom told us in an e-mail. “We’re . . . hoping to get into the Independent Film Festival Boston, which takes place in April, as well as some of the bigger festivals like SXSW and some documentary focused ones like True/False. Because of the way the festivals work, we have to hold off doing any public screenings at least until we know if we’ve got into any of them.’’ If you’re desperate to see the film, you can find a nice trailer at www.southstreetdinermovie.com.