Collection: Temperature Controllers

Temperature controllers are essential devices for precise temperature control across a variety of industrial, commercial, and laboratory applications. Whether you're managing heating or cooling systems, these controllers monitor the temperature in real time and adjust power to your heating element or refrigeration unit to maintain your desired setpoint. On this page, you’ll find a carefully selected range of UK-spec temperature controllers designed to deliver accuracy, reliability, and safety in demanding environments.

Here at Under Control Instruments, our controllers are optimised to handle everything from refrigeration to high-temperature processes. With short-tail transactional intent in mind, our collection includes both on/off thermostats and more sophisticated PID (proportional-integral-derivative) controllers, giving you full control over your heating and cooling. Whether you're retrofitting an existing system or designing a new setup, our temperature controllers help you achieve optimal performance and energy efficiency.

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127 products

Temperature Controllers - Key Features & Benefits

  • Wide Temperature Range: Our controllers support a broad span (for example, –50 °C to +150 °C in models like the 8820 digital thermostat).
  • High Current Relay Output: Built-in relays (e.g., 20 A for some models) eliminate the need for external contactors, reducing cost and complexity.
  • Precision Control: Digital displays with tight tolerance (± 0.4 °C for some units) give far greater accuracy than legacy capillary thermostats.
  • Robust Protection: IP65-rated front panels (dust and moisture resistant) make many controllers suitable for commercial kitchens, damp environments, or refrigeration.
  • Flexible Sensor Options: Use of NTC sensors, thermocouples, or RTD (Pt100) inputs allows you to match the controller to your process.
  • Control Modes: Choose between simple On/Off control or advanced PID control to reduce temperature oscillation and improve stability.
  • Safety & Alarm Features: Many units support over-temperature protection, sensor break detection, and loop-break alarms to safeguard your system.
  • Ease of Installation: Compact formats (e.g., 33 × 75 mm panel mount) make installation straightforward even in tight control panels.

How Temperature Controllers Work

A temperature controller works by constantly comparing the measured process temperature (via a probe or sensor) with a pre-set setpoint. When the actual temperature deviates from the setpoint, the controller sends a signal to either switch on or off a heating/cooling device (in on/off controllers) or to modulate the power more gradually (in PID controllers). In a PID controller, the proportional, integral, and derivative terms are tuned to minimise overshoot and oscillation, achieving stable temperature control. Some units also feature auto-tuning, meaning the controller can learn the dynamics of your system and optimise its own PID parameters.

Ideal Use/Applications For Heat Mats

Temperature controllers are ideal for a wide range of use cases, including:

  • Commercial Refrigeration – controlling compressor cycles to maintain stable fridge or freezer temperatures.
  • Catering & Food Preparation – managing ovens, bain-maries, or food-warming systems.
  • Industrial Heating – regulating heaters, silicone heater mats, or cartridge heaters for manufacturing processes.
  • Laboratory Environments – where precise temperature control is needed for experiments, incubators, or chemical processes.
  • HVAC & Process Control – in systems where maintaining a specific temperature is critical (e.g., in test rigs, environmental chambers).

Important Considerations & Safety Notes

  • Sensor Matching: Ensure that the probe type (NTC, thermocouple, RTD) matches your controller’s input configuration; using the wrong sensor can produce large errors or even damage the controller.
  • Load Handling: Check the current rating of the controller’s relay or output. If your heating or cooling device draws more current than the controller supports, you’ll need an external contactor or SSR (solid-state relay).
  • Environment: While many controllers are IP65-rated for moisture and dust resistance, they should still be installed in a suitable enclosure if used in extremely harsh or wet conditions.
  • Safety Redundancy: For critical or high-risk applications, use a secondary (independent) over-temperature cut-off controller or limiter to prevent runaway heating in case of sensor or controller failure. Indeed, in industrial practice, limit controllers are often used in series with the main temperature controller to prevent dangerous conditions. separate limit controller should monitor the temperature … in case the first sensor or controller fails.”
  • Manual Mode Caution: If using a PID controller with manual mode, be aware that leaving it in manual removes automatic regulation. This can lead to overheating if not monitored.
  • Calibration & Maintenance: Periodically check and (if necessary) calibrate your sensors and controllers to maintain accuracy, especially for critical processes.

Customer Reviews

⭐⭐⭐⭐⭐

"We use these as they are good value and neat units. The buttons aren't too small and fiddly and it is straight forward to program. Very reliable, never had any problems with them."

⭐⭐⭐⭐⭐

"I started out with a cheap Chinese controller for a lead melting pot but within a few months it wouldn't except new data. The new controller although from Brazil is a superb bit of kit very well made and simple to set up, I'm really impressed"

Frequently Asked Questions (FAQs)


What is a temperature controller, and how is it different from a thermostat?

A temperature controller monitors a process temperature via a sensor and actively switches or modulates a heater or cooler to maintain a setpoint. Unlike a basic thermostat, many controllers (especially PID ones) offer precise, stable regulation and additional safety functions.

How do I choose between on/off control and PID control?

Use on/off controllers for simple applications where tight precision isn’t essential (e.g., basic heating or cooling). Choose PID control when you need to minimise overshoot, reduce temperature fluctuations, or handle systems with high thermal inertia.

Which sensor type should I use (NTC, RTD, thermocouple)?

- NTC: Common, cost-effective, good for general use.
- RTD (e.g., Pt100): Very accurate, stable over time, ideal for precision control.
- Thermocouple: Suitable for very high or low temperatures, or fast response times. Your choice depends on your temperature range, budget, and required accuracy.

Can I wire a large heater to a temperature controller directly?

Only if the controller’s output relay can handle the current drawn by the heater. If not, you should use an external contactor or a solid-state relay (SSR) to switch the heater safely.

What safety measures should I take when using a temperature controller?

- Use a secondary over-temperature limiter.
- Ensure correct sensor wiring.
- Regularly calibrate sensors and controllers.
- If using manual control mode, monitor the system to avoid runaway heating.
- Use enclosures where appropriate to protect the controller in harsh environments.

Ready to solve your unique heating challenges? 

Explore our range of temperature controllers, or contact us for a custom heating solution tailored to your exact needs!