Question 92Refrigeration & AC - Assistant Engineer

The correct answer is A) The dry bulb room temperature is controlled by a steam heated reheater and its associated pneumatic control valve. In a large public space air conditioning system, the class "A" air conditioning system uses a steam heated reheater to maintain the desired dry bulb room temperature. The reheater is controlled by a pneumatic control valve that is modulated by the room thermostat to add or reduce steam flow as needed to maintain the setpoint temperature. The other answer choices are incorrect because: B) The reheater is used in both the cooling and heating modes to fine-tune the air temperature; C) The preheater steam flow is not controlled by the space thermostat, but rather by the system controls; and D) It is possible for both the cooling coil and reheater to operate simultaneously to precisely control the air temperature.