a. During the period from October first through May thirty-first, centrally-supplied heat, in any dwelling in which such heat is required to be provided, shall be furnished so as to maintain, in every portion of such dwelling used or occupied for living purposes:
(1) between the hours of six a.m. and ten p.m., a temperature of at least sixty-eight degrees Fahrenheit whenever the outside temperature falls below fifty-five degrees; and
(2) between the hours of ten p.m. and six a.m., a temperature of at least fifty-five degrees Fahrenheit whenever the outside temperature falls below forty degrees.
b. During the period from October first through May thirty-first, all central heating systems required under this article shall be maintained free of any device which shall cause or which is capable of causing an otherwise operable central heating system to become incapable of providing the minimum requirements of heat or hot water as required by this article for any period of time. This subdivision shall not apply to any safety device required by law, or by a rule or regulation of any city agency, to be used in conjunction with a central heating system.