I found this in a cookbook with favorite/most requested recipes from the Knoxville Tennessee newspaper and I adjusted to use what I had on hand. It is so simple but so good and I can control the salt. I usually have grated cheese, crisp bacon and chopped fresh chives on the side so people can add what they want but I like the soup as it is. Leftovers are great
In a 4 quart stock pot add water and salt. Add celery and bring to a boil. Meanwhile you can start to prepare the potatoes and onions. Boil celery for about 10 minutes before adding potatoes and onions; decrease heat and continue to simmer until vegtables are fork tender. Have enough water to just cover the veggies. Do not drain water off after veggies are done.
Meanwhile... melt butter in a saucepan. Add flour and stir. Cook 2-3 minutes, stirring constantly so it will not burn. Add the evaporated milk and cook until thickens and coats the back of a spoon. If this becomes too thick just add a few ladles of the cooking water from the potato mixture. Add this to the potatoes and continue to cook until thickens slightly. Taste and adjust seasoning.