Temperature switches in HVAC applications

What is a temperature switch?

A temperature switch is a device that monitors temperature changes and responds when a preset threshold is reached. It is installed in critical points of the HVAC system, such as compressors, boilers and pumps, and can trigger actions like system shutdowns or cooling activation to prevent overheating.

Benefits of temperature switches in HVAC applications

1. Enhancing HVAC efficiency

When temperatures rise beyond optimal limits, components such as compressors and motors can be damaged, causing the system to lose efficiency. A temperature switch ensures the system does not overheat, which prevents excessive energy consumption.

2. Component protection

One of the most critical functions of temperature switches is to protect HVAC systems from damage caused by extreme temperature conditions. For instance, if the system overheats, components may fail, requiring expensive repairs and resulting in downtime. Temperature switches act as safeguards, automatically shutting down the system or adjusting its operation when thresholds are exceeded. This protection not only extends the system's lifespan but also reduces the risk of major breakdowns and associated repair disruptions.

3. Enhanced Safety

Temperature extremes can create hazardous conditions. Temperature switches help prevent overheating, which could cause fires or damage to pipes and equipment.

Applications across HVAC components

Temperature switches are used across various HVAC components, each with its own specific function. In heating systems, temperature switches can protect boilers from overheating by shutting them down if the temperature exceeds safe levels, thereby preventing damage to heating elements. Similarly, if motor windings overheat in compressors and pumps, temperature switches activate cooling measures or initiate a system shutdown to prevent further damage. Whether in residential, commercial or industrial HVAC systems, temperature switches are integral to the system’s smooth and safe operation.

When selecting a temperature switch, it is important to consider:

• Temperature Range: Ensure the switch operates within the required temperature limits for the given HVAC system.
• Reset Type: Decide whether a manual or automatic reset is needed.
• Materials and Durability: Look for corrosion-resistant, insulating and highly durable materials.
• Certifications: Check for industry compliance (such as IEC standards or UL certifications) to ensure safety and quality.

Temperature switches used in HVAC applications

Bimetal thermal switches: Offering temperature protection, bimetal thermal switches monitor the temperature of key components like compressors, motors and heating elements. If the temperature exceeds a safe limit, the bimetal strip bends, breaking the electrical connection and shutting down the system. This prevents damage to components and avoids costly repairs. These switches are designed to automatically reset once the temperature returns to a safe range.

Current and temperature limiters: These bimetal thermal switches are used in HVAC applications to protect against both overcurrent and overtemperature conditions. Once triggered, the switch remains “off” until it is manually reset. It is essential in critical HVAC systems to prevent damage to compressors, motors and other components. 

Thermal fuses: Unlike thermal switches, which may automatically reset, thermal fuses are single-use devices that permanently break the electrical circuit when a specific temperature is exceeded. They disconnect power if the system overheats due to airflow blockages, motor failures, or electrical faults.

Limitor designs and manufactures high-quality temperature switches and offers multiple configuration options to suit different HVAC applications and meet a variety of performance needs

For applications where temperature needs to be monitored and controlled rather than switched at a specific point, Limitor offers various temperature probes that provide continuous feedback on the temperature of the environment, allowing precise control, monitoring and data logging for HVAC applications.

If you’re looking to improve the efficiency, reliability, and safety of your HVAC system, contact our team to learn more about the customisable solutions we offer to meet the specific needs of your HVAC application.