Preventing Pump Overheating With Thermostatic Technology

11/03/2025

Booster pumps are the backbone of commercial buildings’ water systems, ensuring safe and reliable water distribution when municipal water pressure is not enough. When water demand is low, pumps may run inefficiently, generating excess heat. Over time, this overheating can damage seals, bearings and casings, shorten pump life and reduce system reliability.

This article explores how temperature control technology can safeguard pumps and extend their operational life while saving money and reducing overconsumption of water.

Why a Pump Overheats

When a pump operates at low or no flow (deadheading), the energy that would normally be converted to fluid velocity is instead converted to heat. This internal friction and turbulence rapidly increase the temperature within the pump casing or volute. Prolonged operation under these thermally stressful conditions can have damaging effects.

Excessive heat degrades internal components quickly. Elastomer seals can harden, crack and lose flexibility, resulting in premature leakage and failure. Bearing lubricants thin out as viscosity drops, reducing their ability to protect against friction and wear. The pump casing itself can expand under thermal stress, increasing clearances or causing distortion. Left unchecked, overheating can escalate into catastrophic pump failure, leading to costly emergency repairs, unplanned downtime and production losses. Pumps can also overheat due to debris or blocked airflow.

Methods to Cool Overheated Pumps

There are several methods to avoid or cool overheated pumps so that they do not run into mechanical failure. 

Traditional methods include:

• Operating in bypass mode
• Installing a cooling jacket around the pump
• Fan cooling
• Adding a water cooling system to remove excess heat
• Continually supplying water to cool the pump, resulting in excess costs for overconsumption of water

However, many of these methods are manual or require constant monitoring, which is not feasible.

A cost-effective and efficient approach to cooling water pumps is thermostatic thermal relief valves, which are designed to automatically discharge over-temperature water to avoid seal degradation and pump system damage. When water inside a closed system heats up beyond a safe level, the valve modulates open to discharge it and allows cooler water to enter through the pump suction. The valve’s main function is to maintain safe temperature levels. This translates directly to longer mean time between failures (MTBF), fewer maintenance calls and increased equipment uptime.

What Is a Wax Motor?

At the heart of thermostatic valves is the wax motor, a simple yet effective device that can be used in various critical applications, from regulating engine temperatures in automobiles to controlling water temperature in washing machines.

A wax motor is a linear actuator that uses the phase change properties of a paraffin wax blend to convert thermal energy to mechanical energy. The wax, when heated, undergoes a significant volumetric expansion as it transitions from a solid to a liquid state, which can be as much as 20% of its original volume. This expansion extends the piston within the thermostatic valve, producing a usable stroke that opens or closes the valve.

What makes this technology so unique is that thermostatic valves modulate based on temperature alone, not pressure or flow. Unlike pressure regulating valves or flow control devices that can be influenced by system pressure fluctuations, a thermostatic valve's response is solely controlled by the localized fluid temperature it senses. This characteristic ensures consistency, even in demanding and dynamic industrial environments where pressure spikes or flow variations might confound other control methods.

Protecting Pump Systems in Real-World Applications

Thermal relief valves are vital on pumps in commercial buildings and industrial facilities that need heat removal, especially in high-demand facilities, such as:

• High-rise residential buildings
• Hotels
• Hospitals/healthcare facilities
• Office buildings
• Schools/universities

Benefits of Pump Thermal Relief in Applications

In many applications, a pressure relief valve is installed and set at a pressure below the deadhead pressure. This can lead to cooling water running endlessly to drain regardless of its need, resulting in water waste and unproductive operation. Installing a thermostatic valve on the volute discharge tap will automatically control the cooling water supply, eliminating the need for manual adjusting and regulating a constant water outlet temperature.

Thermostatic valves continuously monitor the water temperature and adjust the water required. This reduces unnecessary water usage, lowering operating costs.

There are many benefits to using thermal relief valves on pumps:

• Self-actuating and mechanical: A defining feature of thermostatic valves is that they require no electricity to operate, which reduces maintenance-related expenses.
• Modulating function: The valves adjust their position based on the temperature.
• Compact and low mass: These valves can be installed in seconds and save space due to not needing extra piping.

A Proactive Strategy for Modern Facilities

Pump overheating is a silent threat that can damage seals, bearings and casings long before visible failure occurs. By automatically responding to temperature—not pressure or flow—thermostatic relief valves extend pump life, reduce maintenance costs and conserve water without adding system complexity. Facilities that adopt thermostatic technology are not just reacting to pump failures; they are proactively safeguarding performance, reliability and efficiency for years to come.

In today’s environment of rising costs and increasing demand for resource efficiency, thermostatic valves offer plant operators a straightforward, future-ready solution: reliable protection that keeps pumps cool, systems safe and operations running without interruption.