Environmental control of liquid cooled electronics

A system and computer program product are provided for controlling liquid-cooled electronics, which includes measuring a first set point temperature, Ta, wherein the Ta is based on a dew point temperature, Tdp of a computer room. A second set point temperature, Tb, is measured, wherein the Tb is based on a facility chilled liquid inlet temperature, Tci, and a rack power, Prack, of an electronics rack. A Modular Cooling Unit (MCU) set point temperature, Tsp, is selected. The Tsp is the higher value of said Ta and said Tb. Responsive to the selected Tsp, a control valve is regulated. The control valve controls a flow of liquid that passes through a heat exchanger.