N.Y.C. Admin. Code § 24-156: § 24-156 Use of fuel burning equipment without using apparatus prohibited.

(a) Except as provided in subdivision (b) of this section, no person shall cause or permit the use of fuel burning equipment that is fitted with apparatus, other than experimental apparatus, unless the required apparatus is used.

(b) If fuel burning equipment is fitted with apparatus and is designed to use more than one kind of fuel, the equipment shall not be used unless the apparatus appropriate for the particular fuel is used.