Question 472General Subjects - Assistant Engineer

The correct answer is A) The thermostat controlling the preheater steam flow is set several degrees lower than the design cooling coil off-coil temperature to prevent simultaneous flows. This is correct because the system is designed to avoid simultaneous heating and cooling, which would be inefficient. By setting the preheater thermostat a few degrees lower than the cooling coil off-coil temperature, the system ensures that the preheater will turn off before the cooling coil turns on, preventing the waste of energy from heating and cooling at the same time. The other options are incorrect because B) and C) would allow simultaneous heating and cooling, while D) would not prevent it.