Looking at Na-Mor, Inc. v. Espinosa, CV 186889, 1999 Conn. Super. LEXIS 1480 (1999), it doesn't look like the state law helps you much (at least in terms of a rent abatement) if the problem is the adequacy of the hot water supply as opposed to there not being any hot water at all. Your local government may have an ordinance that regulates temperature of water in rental units; I suggest checking with the department that oversees rental housing.

The landlord may be dealing with a Catch-22: Trying to keep water temperatures from being unsafe, while trying to provide hot water to a lot of units (perhaps with an aging water heater).