Drain the clams' fluid into a medium saucepan, then set the clams aside. Combine the potatoes, onions, and celery with the clam liquid.
The potatoes should be simmered covered for about 20 minutes at medium heat with just enough water to barely cover the potatoes.The butter should be melted in a big pot.Stir in the flour after adding the butter.
Whisk in the heated half-and-half gradually.For about 5 minutes, cook and stir until smooth and thick.Add half to three quarters of a cup of water or clam broth to make the chowder thinner.Add the clams, veggies, salt, pepper, sugar, and cooking liquid to the pan.
Stir thoroughly and, if required, adjust the spices.