(a)    Any person holding a license to permit him to engage in the business or occupation of installing, altering, repairing, cleaning, or adding to any warm air heating system who shall fail to procure a renewal of license as herein provided within thirty days from the date of its expiration shall, before he is issued such license, be required to undergo examination with payment of the fee therefor as in the original instance.
   (b)    Renewals of licenses may be issued by the City Clerk or his clerk or by the clerk of the Building Inspector.
(1978 Code Sec. 5-60)