Fluid temperature control is a parameter that is often overlooked in hydraulic systems, where the focus is typically on pressure and flow rate. Overheated hydraulic oil loses viscosity and accelerates wear on pumps and valves.
Elettrotec’s TER adjustable immersion thermostat was developed specifically to address this critical issue through a deliberate technological choice: direct bulb temperature sensing instead of external pipe surface contact.
Immersion Thermostat: Why We Chose Liquid Expansion Technology
The TER uses liquid expansion technology. In environments such as pump rooms and hydraulic power unit enclosures, where vibration and electromagnetic interference are common, a mechanical operating principle provides greater robustness than an equivalent electronic sensor. The sensing bulb is immersed directly in the process fluid rather than being mounted on the external surface of the pipe. This eliminates the thermal lag that occurs when the temperature measurement must pass through the metal wall of the piping.
The output contact is of the SPDT type. This configuration allows the TER to be wired in either normally open (NO) or normally closed (NC) mode, enabling it to match the system’s safety logic without requiring any change to the component.
Thermostat for Hydraulic Systems: TER’s Role in Hydraulic Power Units
In hydraulic power units, the TER does not operate alone.
In hydraulic power units, the TER is installed on the tank or oil circuit within a sensor layout that includes the GRL level switch for electrical level monitoring, PMC or PSK pressure switches and PTL or EPX02 pressure transmitters for continuous pressure measurement, the PDE differential pressure switch for filter clogging monitoring, and FPR flow switches for flow detection.
The industrial thermostat is therefore part of a temperature control system integrated with the other sensors in the installation.
The most critical point for thermal control is the tank, where the fluid remains longer and accumulates heat if the heat exchanger is undersized. For this reason, the TER is installed in direct contact with the oil inside the tank, not only along the delivery line.
Thermostat for Pumps and Boilers: Control on Delivery Pipelines
On delivery pipelines, the TER provides automatic control of pumps and boilers.
The adjustable set point allows the switching threshold to be calibrated according to the process fluid, whose composition and target viscosity vary from one system to another.
This flexibility reduces the number of custom variants required by hydraulic and pneumatic customers.
TER Industrial Thermostat Configurability
The TER is available in various combinations of temperature ranges, stem lengths, and process connection threads.
This configurability addresses the dimensional differences of tanks and threaded connections across different systems, which are often not standardized even within the same production line.
Being able to change the stem length and thread without changing the product family reduces engineering specification time when designing series-produced hydraulic power units.
In Summary
Within our product range, TER is the answer to a specific application need: a reliable adjustable immersion thermostat for demanding environments, fully integrable into the sensor system of a hydraulic power unit and configurable without compromise in terms of dimensions and threaded connections.
For complete technical specifications (temperature ranges, available stem lengths, and thread options), please refer to the product datasheet.