In a large pot of boiling water, cook the elbow macaroni according to the package instructions, which should take about 12 minutes.

During the last 2 minutes of the macaroni's cooking time, add the frozen peas to the pot.

Drain the macaroni and peas using a colander. Let them cool for about 10 minutes, gently stirring occasionally to release heat.

In a large mixing bowl, combine the cooled macaroni and peas with the chopped celery, pimentos along with their juice, chopped sweet pickles plus the pickle juice, mayonnaise, salt, and celery seed.

Stir all the ingredients together until the macaroni is evenly coated with the dressing.

Cover the bowl and refrigerate the salad for at least 1 hour to allow the flavors to meld and the salad to chill completely.