Collection: Cartridge Heaters

Key Features & Benefits

• High Watt Density Options - Delivers concentrated, powerful heating where you need it most.
• Wide Range of Sizes - Available in multiple diameters (e.g., 6.5 mm, 10 mm, 12.5 mm, 16 mm) and imperial equivalents to suit a broad variety of applications. 
• Long Service Life - Constructed from high-grade stainless steel sheaths and NiCr conductor for durability and longevity. 
• Push-Fit Installation - Designed for easy insertion into drilled cavities, reducing installation complexity. 
• High Temperature Capability - Some cartridges are engineered to operate at temperatures up to 800 °C for extreme applications.
• Customisable Leads and Zones - Options for fibreglass leads, thermocouples, segmented heating zones, and more.
• Efficient Energy Use - Efficient heat transfer minimises lost energy and improves thermal responsiveness. 

How These Products Work

Cartridge heaters operate on the principle of resistive (Joule) heating: electrical current flows through a resistance wire (typically NiCr), which heats up. This resistance wire is tightly packed with insulation material and enclosed in a stainless-steel sheath. The resulting heat is then transferred directly to the metal surface into which the heater is fitted, thanks to a snug, push-fit installation which minimises air gaps.

Depending on the design:

• Standard cartridges produce uniform heat along their heated length.
• High-density cartridges pack more wattage per unit volume, achieving higher temperatures.
• Immersion (NPT-threaded) cartridges can be screwed into tanks or vessels to heat liquids or gases.
• Optional thermocouples or integrated temperature sensors allow for precise temperature monitoring and control.

Because of their construction, heater cartridges provide very efficient, focused, and controllable heat in a compact form factor.

Ideal Use / Application

Cartridge heaters from Under Control are particularly suited for:

• Heating dies, moulds and platens in injection-moulding, stamping or press machines. 
• Metalworking and tooling applications where precise, localized heating is required.
• Industrial heating systems, such as heating blocks, jigs or assemblies.
• Immersion heating, using NPT-threaded cartridges for liquids or gases in vessels and tanks. 
• High-temperature applications in lab equipment, test rigs or specialised manufacturing.

These heaters are ideal when you need a compact, reliable and high-performance heat source in tight or confined assemblies.

Important Considerations & Safety Notes

1. Correct Size is Critical: Always choose a cartridge heater that fits snugly into the drilled hole - too much air gap can cause overheating and eventual failure. 
2. Voltage & Watt Density: Ensure the voltage and watt density are appropriate for your application. Incorrect specifications can significantly reduce heater life. 
3. Moisture and Contaminants: Moisture ingress or dirty environments can reduce insulation integrity. Use sealed or moisture-resistant variants if your application demands it.
4. Mounting and Leads: Secure leads and avoid excess vibration or movement, which can stress the heater and degrade performance over time.
5. Thermal Cycling: Frequent, rapid heating/cooling cycles can stress the resistance wire. Choose the right watt density and consider integrated thermocouples to manage cycling.
6. Qualified Installation: Always have a qualified technician or engineer install or replace cartridge heaters, especially in critical industrial or high-power applications.

Customer Reviews

⭐⭐⭐⭐⭐

"Fantastic.

Used in a dimplex towel rail and about a tenth of the original cost."

⭐⭐⭐⭐⭐

"Heating cartridge

Have ordered these for many years now. excellent quality & great prompt service from Under Control."