Updates from our CEO Paul Darley regarding Coronavirus

Fire Pumps, Fire Apparatus, Fire and Defense Equipment

Just Ask Engineering Spring/Summer 2020

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Darley’s new thermal relief valve is your answer. Our thermal relief valve is a device that ensures hot scalding water is not about to be discharged onto an unsuspecting person and also to safeguard the pump itself. We offer our thermal relief valve in two options: 12VDC or 24VDC. Our thermal relief valve opens when it senses 120˚F (49˚C) and allows the hot water to escape from the pump, assuming you have cooler water going into your pump to replace the hot water that has just escaped through the opened thermal relief valve. Essentially, our thermal relief valve assembly is a thermal switch that controls a ball valve which opens when the thermal switch senses hot water. This opened ball valve then lets hot water escape from the pump. Once enough hot water has been replaced by cold water, the thermal switch will close the ball valve which stops water from escaping the pump. This system will wait until it senses hot water again and repeat the process automatically.

Now back to the question. Since many of you have never seen your thermal relief valve open up because you have never encountered hot water, Darley has just added a “Push To Test” button on the thermal relief valve’s pump panel plaque. Simply press this button and it forces open the ball valve that the thermal switch typically controls. Upon pressing, when there is positive water pressure within your pump, a panel light should ignite, and water will be seen escaping from your thermal relief valve. You now have a way to ensure your thermal relief valve opens. When you release the button, the light will go off and the ball valve will close if no hot water is detected in your pump.

Thermal relief valves are an available option to add to any Darley pump, from our smallest portable to our largest midship pump. Some assembly will be required and you will need to provide electrical power for this device.