Begin by boiling a large pot of water. Add 1 pound of elbow macaroni and cook according to package instructions until al dente. Drain and rinse with cold water to stop the cooking process, then set aside to cool.

In a large mixing bowl, combine the mayonnaise, white vinegar, sugar, yellow mustard, kosher salt, and coarse ground black pepper. Whisk until the dressing is smooth and well blended.

Add the finely chopped celery, sweet relish, and chopped pimento peppers to the dressing. Next, fold in the cooled elbow macaroni. Gently mix until all ingredients are well coated with the dressing.

Cover the bowl with plastic wrap or a lid. Refrigerate the salad for at least 1 hour. For best results, let it chill overnight to allow the flavors to meld together.