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The Carlo Gavazzi Group


Air-handling units

Proportional control of heater packs

Heater banks are used in AHUs to control the humidity of the air supplied to the building. For a better energy efficiency, rather than switching the heaters on full power, proportional controllers can modulate the heating power based on the level of an analog input.
Our proportional controllers - RGC1P , RGC2P and RGC3P series are suitable for 1-phase and 3-phase heaters. With full cycle switching method, the heater power can be modulated from 0% to 100% with no EMC disturbance. Full cycle switching is available on the RGC1P via the setting on the selector switch and on the RGC2P and RGC3P C1 models.

Speed control of centrifugal fan

The amount of air exchanged in the AHU can be regulated via the speed of a centrifugal fan. Variable frequency drives (VFDs) are used for this purpose.
Our RVLF series of VFDs is available in single-phase (200 - 230 V) and three-phase (380 - 480 V) input models up to 11kW (15HP). It comes with integrated EMC filter and can be controlled via analog voltage or current inputs.

Detecting pump failures in air handling units

Air-handling units (AHUs) can be coupled to chillers that feed chilled water to a heat exchanger on of the AHU stages. The chilled water is circulated by a pump. Failures on the pump will cause discomfort to building occupants.
Our EISH current monitoring relay3euELe2SVSg can be used to detect whether the pump is running by monitoring its current. If the pump is off, the EISH provides a signal to system controller that can alert the service team for a timely maintenance intervention.