A pumped refrigerant cooling system for use in a row of equipment racks (26, 78) configured to contain electronic equipment, the pumped refrigerant cooling system comprising: a communication network; a refrigerant distribution unit in fluid communication with a chilled refrigerant supply by a supply line and in fluid communication with a heated refrigerant return by a return line, the refrigerant distribution unit configured to pump liquid refrigerant by a liquid supply line to at least one cooling module and being coupled to the communication network; the at least one cooling module in fluid communication with the refrigerant distribution unit by the liquid supply line and a vapor return line, the cooling module being coupled to the communication network, the cooling module including an evaporator and at least one fan configured to direct air over the evaporator; a sensor package coupled to the communication network, the sensor package being configured to monitor temperature comprising supply air temperature and pressure reference points comprising evaporator pressure provided in the pumped refrigerant cooling system and the equipment racks (26, 78); and a controller forming part of the cooling module and coupled to the communication network and the sensor package, the controller, based on information obtained from the sensor package, being configured to manipulate the flow of refrigerant through the evaporator by controlling the delivery of refrigerant to the evaporator and being configured to manipulate the flow of air over the evaporator by controlling the speed of the fan characterised in the cooling module further including an electronic evaporator pressure regulating valve disposed in the return line between the evaporator and the refrigerant distribution unit, the electronic evaporator pressure regulating valve being configured to regulate evaporator pressure to maintain a desired cooled air exit temperature from evaporator, wherein the controller of the cooling module further includes a PID loop being configured to regulate the electronic evaporator pressure regulating valve position as needed to maintain a predetermined saturated evaporating temperature and a supply air temperature controller PID loop being configured to eliminate an error between a supply air temperature set point and the supply air temperature as read by one or more sensor to maintain a constant supply air temperature; wherein the supply air temperature controller PID loop is configured to constrain the saturation temperature set point such that the saturation temperature set point is above a dew point of the environment and less than the supply air temperature set point. a communication network; a refrigerant distribution unit in fluid communication with a chilled refrigerant supply by a supply line and in fluid communication with a heated refrigerant return by a return line, the refrigerant distribution unit configured to pump liquid refrigerant by a liquid supply line to at least one cooling module and being coupled to the communication network; the at least one cooling module in fluid communication with the refrigerant distribution unit by the liquid supply line and a vapor return line, the cooling module being coupled to the communication network, the cooling module including an evaporator and at least one fan configured to direct air over the evaporator; a sensor package coupled to the communication network, the sensor package being configured to monitor temperature comprising supply air temperature and pressure reference points comprising evaporator pressure provided in the pumped refrigerant cooling system and the equipment racks (26, 78); and a controller forming part of the cooling module and coupled to the communication network and the sensor package, the controller, based on information obtained from the sensor package, being configured to manipulate the flow of refrigerant through the evaporator by controlling the delivery of refrigerant to the evaporator and being configured to manipulate the flow of air over the evaporator by controlling the speed of the fan characterised in the cooling module further including an electronic evaporator pressure regulating valve disposed in the return line between the evaporator and the refrigerant distribution unit, the electronic evaporator pressure regulating valve being configured to regulate evaporator pressure to maintain a desired cooled air exit temperature from evaporator, wherein the controller of the cooling module further includes a PID loop being configured to regulate the electronic evaporator pressure regulating valve position as needed to maintain a predetermined saturated evaporating temperature and a supply air temperature controller PID loop being configured to eliminate an error between a supply air temperature set point and the supply air temperature as read by one or more sensor to maintain a constant supply air temperature; wherein the supply air temperature controller PID loop is configured to constrain the saturation temperature set point such that the saturation temperature set point is above a dew point of the environment and less than the supply air temperature set point.