John A. Quinn, 62, head of a mechanical contracting firm bearing his name, died of a heart attack April 19 while on vacation in Glendalaugh, County of Wicklow, Ireland.

He founded John A. Quinn, Inv., in 1950. The Rockville firm became one of the largest plumbing, heating, ventilating and air conditioning contractors in the area.

The company worked on numerous residential developments, high-rise apartments and office buildings here and in the Ocean City, Norfolk and Baltimore areas.

Born in Washington, Mr. Quinn was a graduate of St. John's College High School and attended Columbus Law School of Catholic University. He served with the Seabees in the South Pacific in World War II.

After the war, he worked for the George Weitzel Plumbing Co. until establishing his own firm.

Mr. Quinn was a director of the District of Columbia National Bank. He was a former director of the National Bank of Rosslyn.

In 1968, he established the John A. Quinn Foundation for philanthropy and directed its activities until his death.

He was a member of the board of the Merrick Boys Camp, the Presidents Club of the Catholic University Alumni Association and the Congressional, Rehoboth Beach and Chantilly country clubs.

He is survived by his wife, Margot, of the home, "Big Q Ranch," in Chantilly; a son, J. Gregory Quinn, N.S.J., of Wernersville, Pa., and three brothers, Harold J., of Silver Spring, George J., of Washington, and Brother William Quinn, F.S.C., of Philadelphia.

The family suggests that expressions of sympathy may be in the form of contributions to the Quinn Scholarship Fund at St. John's College High School.