Chillers and Rooftops

Our DIN-rail mount meters include models for both current transformer (CT) connection and direct connection. They combine compact housing with a comprehensive and user-friendly display, delivering accurate and accessible energy data in a space-saving format.

In HVAC systems, the compressor is the core component — whether centrifugal, scroll, or screw — and is typically driven by an asynchronous motor.
Failures due to incorrect phase sequence, phase loss, or poor mains quality are common, often leading to reverse rotation, overheating, and ultimately, extended and costly downtime.
To prevent these issues, installing a monitoring relay that checks phase sequence, phase loss, and mains quality is a proven best practice.
Our DPA51 and DPB51 monitoring relays are widely used in compressor-based applications, thanks to their compact size, self-powered operation and wide operating voltage range. These features make them ideal for reliable and space-efficient protection in HVAC environments.

Commercial rooftop units (RTUs) and chillers use a variety of compressor types — including scroll, piston, screw, and centrifugal compressors.
Our range of soft starters is designed to support all types of induction motor-driven compressors.
The RSBD and RSBT soft starters are specifically engineered for scroll compressors. They feature a self-learning control algorithm that automatically optimizes inrush current reduction at every start, with no user configuration required.
For piston and screw compressors, the RSGD and RSGT models offer greater flexibility, allowing for customizable settings to meet specific application needs.
These soft starters ensure reliable performance, reduced mechanical stress, and optimized energy use across a wide range of HVAC systems.

In rooftop units (RTUs) and chillers, the speed of AC condenser fans can be effectively controlled using the phase angle control principle.
By adjusting the output voltage in proportion to an analog input signal, solid-state proportional controllers—such as the RGC1P and RGC3P series—regulate the speed of low starting torque, low inertia induction motor fans. This results in reduced power consumption and improved energy efficiency.
Multiple condenser fans can also be grouped and managed using a single proportional controller, simplifying system architecture and reducing installation complexity.

To be placed on the market, heat pumps must meet increasingly strict seasonal efficiency requirements. Achieving high efficiency even during partial load operation calls for advanced compressor technologies capable of operating at both low and high speeds.
As a result, permanent magnet (PMAC) and brushless DC (BLDC) compressors are now widely adopted in modern heat pump systems.
Our RVPM variable frequency drive (VFD) is designed to support this evolution. It is compatible with single-phase or three-phase input, and PMAC, BLDC, and induction motor compressors
The RVPM offers flexible, reliable control to maximize energy efficiency across a wide range of heat pump applications.

Ensuring that critical system loads operate when required is essential—especially in pump and fan applications, where unexpected downtime can have serious consequences.
By enabling the early detection of motor faults, our monitoring solutions help trigger timely corrective actions, reducing the risk of unplanned interruptions.
Our ON/OFF monitoring range includes the EISH, DIA02, DIA53, and DIB01 100A models. This range allows for the monitoring of all load types, from very low currents (20 mA) to high loads (up to 100 A). Thanks to both relay and solid-state outputs, these devices can easily interface with various control systems, ensuring flexible and reliable integration.

Integrating dedicated timers into rooftop unit and compressor control systems improves overall efficiency, reduces maintenance costs, and extends the lifespan of critical equipment.
The DAC51 timer handles star-delta motor starting independently, eliminating the need to rely on the main controller. This simplifies maintenance and reduces replacement time and cost in case of relay output failure.
The DAA51 timer manages compressor start-up by distributing high inrush currents over time. This prevents power peaks, protects other devices connected to the mains, and ensures stable operation. Additionally, it enforces the maximum number of starts per hour, minimizing mechanical stress and improving system reliability.
These solutions support optimal system performance without compromising comfort or energy efficiency.