Monthly Archives: April 2026

Carel is one of the world's leading manufacturers of controllers, humidifiers, and electronic components for HVAC/R and refrigeration applications. iACS has stocked and supported the Carel range since 2011 and holds one of the most comprehensive Carel inventories in the UK. This guide covers the key Carel controller families, their applications, and how to select the right model.

Planned preventative maintenance (PPM) of HVAC controls is one of the most cost-effective investments a facilities team can make. A controls fault that goes undetected can run a system incorrectly for months — wasting energy, causing discomfort, and building towards a more expensive breakdown. This checklist covers everything that should be inspected, tested, and documented on a typical HVAC controls PPM visit.

The term Building Management System gets used loosely — sometimes to mean a simple time clock and thermostat setup, sometimes to describe a sophisticated, multi-protocol, enterprise-level monitoring platform. This guide explains what a BMS actually is, what it does, how it integrates with HVAC field devices, and when your project needs one.

If you are specifying a new HVAC controls system or integrating new equipment into an existing installation, the choice of communication protocol will define what is possible, what is practical, and what will cost you time on site. BACnet and Modbus are the two protocols you will encounter in almost every commercial HVAC project. This guide explains both clearly, compares them honestly, and tells you which to use when.

An air handling unit (AHU) is the central hub of a mechanical ventilation system — the piece of equipment that conditions and distributes air throughout a building. Understanding how AHU controls work is fundamental for anyone specifying, installing, or commissioning HVAC systems.

This guide covers the anatomy of a typical AHU, the control components used at each stage, sensor placement, actuator and drive selection, and the commissioning steps that ensure the system operates as designed.

If you work in building services, facilities management, or HVAC installation, understanding controls is not optional — it is the difference between a system that runs efficiently and one that runs up energy bills and callbacks. This guide covers everything: what HVAC controls are, how they work, the components involved, how they communicate, and how to select the right controls for your application.