This range of FCUs has water-side control and maintains constant volume regardless of downstream pressure drop.
The key to the lower energy use is the use of energy-efficient electronically commutated motors to drive the twin impellers.
These FCUs are designed to operate at constant volume against pressures from 10 to 60 Pa. The volume can be set at the factory using a potentiometer to send a constant voltage to the fan power module. The only commissioning requirement is to balance the airflow through each branch.
Until the room load is met, an EHW 230 fan-coil unit runs at the selected speed and duty and the related noise level. Once the temperature setpoint is reached and the space is under control, the unit throttles back by automatically reducing fan speed in response to a setback signal from the controller.
