Boil potatoes until tender.

Peel and slice the potatoes thinly.

Fry bacon until crispy and drain excess fat.

Chop onion and saute in bacon fat until golden brown.

In a separate bowl, blend flour, sugar, salt, celery seed, and pepper.

Cook the flour mixture until smooth and bubbly, then remove from heat.

Stir in water and vinegar.

Bring the mixture to a boil, stirring constantly.

Boil for one minute.

Carefully stir in the sliced potatoes and crumbled bacon.

Cover the salad.

Let the salad stand until ready to serve.

Serve warm or at room temperature.