Calectro CRC/CRT - Calectro

CALECTRO CR

A family for perfect indoor climate

Say hello to Calectro CR. Our new product family for demand‑controlled ventilation, consisting of controllers and transmitters with CO2, temperature, and humidity regulation. These units allow you to control the indoor climate with high precision and easy installation, available both for room mounting and for installation in ventilation ducts.

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Calectro CR - for an energy-efficient indoor climate

Calectro CR is a family of controllers and transmitters that, with the help of built‑in CO2, temperature and humidity sensors, can reliably and energy‑efficiently control cooling, heating and ventilation in a room. The units have different functions and can be used either as pure transmitters connected to a central control system, or as standalone controllers that directly control radiators, dampers and cooling coils.

The central component in all Calectro CR products is the built‑in CO2 sensor, which quickly determines whether the room is occupied and then adaptively adjusts ventilation and heating as needed. In spaces used only during parts of the day, this can significantly reduce energy costs – full ventilation is required when the room is occupied, but when it is empty, a basic airflow is sufficient.

Two product lines – different functions, same high quality

CRC – Controllers

The CRC controllers are available in two versions: one for wall mounting in rooms and one for installation in ventilation ducts.
The room mounted controllers measure CO2 concentration, temperature and humidity via built in sensors, and then control connected devices completely independently. Both models offer the same intelligent functions for demand controlled ventilation.

CRT – Transmitters

The CRT transmitters are available in two versions: with or without display.
The room‑mounted transmitters measure CO2 concentration and temperature and report these values to a central control system.
CRT is a simple and reliable choice when accurate measurement is needed without local control.

CRC-A-MB-24

Wall‑mounted controller

UG8-CRC-A-MB-24

Duct‑mounted controller

CRT-A-24

Wall‑mounted transmitter

CRT-D-A-24

Wall‑mounted transmitter with display

Demand‑controlled ventilation based on CO2 levels

At the core of all Calectro CR products is the built‑in, self‑calibrating CO2 sensor. Since carbon dioxide is a natural component of exhaled air, its concentration serves as an excellent indicator of how many people are present in a room. The more occupants, the higher the CO2 levels rise.
Both the transmitters and controllers in Calectro’s CR series use this information to regulate the indoor climate with high precision – in an energy‑efficient and demand‑adapted way.

Temperature and humidity measurement

Ventilation may also be required due to changes in temperature or humidity – for example during strong sunlight, high occupancy, or in environments with highly variable moisture levels. Typical examples include commercial kitchens or changing rooms with showers.

All units in Calectro’s CR series are equipped with an integrated temperature sensor.
The controllers – both room‑mounted and duct‑mounted versions – also include a built‑in humidity sensor, allowing the ventilation system to compensate for these conditions as well.

Example installation CRC-A-MB-24

Control of heating, cooling and ventilation in a room with CRC

The example below shows a wall-mounted CRC-controller (1) that measures carbon dioxide, temperature, and relative humidity via its built-in sensors. The controller is directly connected to an air damper (2), but measurement data can also be forwarded to a BMS system via Modbus (6). If needed, a PIR motion detector (3) can be connected directly to the CRC controller for faster response time and increased efficiency. When the room is empty, the air damper is open for basic airflow, but when presence is detected – and if any of the measured values, such as CO2 level, exceed the setpoint – the damper opens further to increase the supply of fresh air. The CRC controller also has separate outputs for controlling heating and cooling, for example via radiators (4) or a cooling coils (5). This ensures that the indoor climate is maintained at the desired level – in the most energy-efficient way possible.

Quick installation with preconfigured functions

The controller in Calectro’s CR series come with 15 preset functions, designed to meet common needs in ventilation, heating, and cooling. The installer easily selects the correct function by setting DIP switches directly on the unit’s circuit board – without power supply or computer. Each function includes predefined values that enable control of one to four outputs. If the settings do not suit the current project, they can be easily adjusted or adjusted via Modbus.

Find the preconfigured function that fits your application with Calectro’s CRC Function Selector

Example scenario – Gym facility

In this scenario, the indoor climate is controlled in a gym facility that is used sporadically, with high occupancy and activity during short periods. Both ventilation and heating need to be managed. When the facility is not in use, a base airflow should be maintained, and when presence is detected, ventilation should be regulated. After the activity ends, there is a 10-minute afterrun time to air out the space before the next training session.

Installed units:

Wall mounted room controller, Damper actuator, Motion detector, Radiator

Wiring diagram – wall‑mounted controller

Selected preset on the wall-mounted room controller

With the units installed and the requirements defined in the scenario, we have in this case selected preset 8, although other presets would also have been possible.

Example scenario – Elderly care home

In this scenario, the indoor climate is continuously regulated in a standard-sized care home. Ventilation, heating, and cooling all need to be controlled, and no central control system is used.

Installed units:

Duct mounted room controller, Damper actuator, Radiator, Cooling coil

Wiring diagram – duct‑mounted controller

Selected preset on the duct-mounted room controller

With the units installed and the requirements defined in the scenario, we have in this case selected preset 3, although other presets would also have been possible.

Why choose a product from the Calectro CR family?

15 preset functions – easy configuration via DIP switch

All controllers in Calectro’s CR series are equipped with 15 preset functions that can be quickly selected via DIP switches inside the unit. These cover most typical scenarios encountered by installers, allowing the units to be configured even before installation – without requiring power.

Discover our function selector – a smart tool that helps you quickly find the right function and configure your CRC controller, with clear step-by-step instructions for the DIP switches. Read more on page 7.

Easy installation – no power required during configuration

Both duct and wall-mounted controllers in Calectro’s CR family can be configured before installation, without needing power connected to the unit. This means settings can be made in advance, saving time and reducing the risk of errors during installation.

Control function for commissioning

During airflow adjustment in a room, preset 15 on the CRC controller can be used. This function sets all outputs to 100%, opening dampers and valves fully – without the installer needing access to ceiling spaces or making manual adjustments on the unit.

Full control with Modbus – configure via PC

If the unit’s presets need to be adjusted, or if you want full control over the controller, it can be easily customized to your specific requirements via PC and Modbus software. For example, you can adjust the P-band for CO2 or temperature control to optimize regulation according to desired values.

Manufactured in Sweden – high quality and local production

All units in Calectro’s CR series – as well as most other products in our portfolio – are both designed and manufactured in Sweden. Components from leading suppliers, short transport routes, and efficient production contribute to a product range known for its consistently high quality. For international customers looking for reliable, locally produced European technology, Calectro represents a sustainable and trustworthy partner.