Lennox International Inc. swung to a profit in the fourth quarter as higher sales from its heating and refrigeration units helped offset service business losses. The Dallas-based company said fourth-quarter net income was $5 million, or 8 cents per share, compared with a net loss of $40.3 million, or 72 cents per share in the same period last year. The loss in 2001 included an after-tax restructuring charge of 50 cents a share. Net sales fell 3% to $704.3 million from $727.1 million a year earlier.