The air temperature of the Air Handling Unit is controlled by a sensor in the outlet. The secondary side of the injection circuit circulates a constant flow through the coil maintaining a uniform temperature throughout the entire coil.
When the control system calls for higher or lower temperature on the air outlet, the PICV valve opens or closes to allow heating or cooling water from the primary side of the injection circuit to enter the secondary side. The temperature in the coil then changes giving an almost direct relation between the temperature in the coil and the power output from the coil.
