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The System

BA HERCS's self-actuated control systems consists of a case iron valve body and two actuators with liquid (mineral oil) filled sensors, that provides the most accurate and reliable temperature control for hot water system in the industry.

Operating Principle

Proportional control is the natural control mode of self actuated valves. A change of hot water temperature (i.e. A rise or fall of 1°F) will produce a specific volume change within a sensor bulb which is filled with mineral oil. In turn, this will move the thrust pin and the valve head by exactly the same amount.

Such a simple relationship between temperature change and valve plug movement enables BA HERCS to offer a sensor and valve combination which can provide predictable temperature within +/- 4° F under varying hot water load demands.

Self-Actuated Control System

Advantages

* FACTORY CALIBRATION: Each system comes with a calibration from the factory so no time is wasted at the job site. “Dial in” the desired temperature when installation is complete.

* NO ELECTRIC/PNEUMATIC CONTROL COST: Self-actuated temperature control systems draw their operating energy from the heat of fluids in which the sensor is immersed. No external electricity or pneumatic control air is required, reducing installation and operating costs.

* LEAK FREE VALVE DESIGN: A packless bellows gland in the control valve eliminates steam/water leakage, thus reducing maintenance costs.

* ACCURATE AND RELIABLE OPERATION: Precalibrated temperature scales provide linear adjustment of temperature set point.

* SAFETY TEMPERATURE LIMITER: BA HERCS offers as a standard, a second sensor the “Safety Temperature limiter” overheat protection control system which can provide a failsafe cut-out limit against high discharge temperature. The safety temperature limiter is adjustable and will closed the valve in a over temperature situation with no external electricity needed.

Temperature Controller and Safety Temperature Limiter

Optional Secondary Overheat

Protection System

When requested, BA HERCS can provide a secondary overheat protection system in addition to the standard self-actuated temperature control system with safety temperature limiter. Overheat protection system consists of two components: high limit aquastat and 1/2” blow down solenoid valve.

When the sensor in the high limit aquastat detects a high temperature in the hot water system, the aquastat opens the 1/2” solenoid valve and drains the overheated water. (The solenoid valve must be piped to a floor drain)

For Pneumatic valve another solenoid valve is added to the air piping between the controller and control valve.

REMOTE ALARM: If desired, this high limit cut-out signal can be linked to a remote alarm system via a micro-switch which will make or break the circuit when the cut-out is activated.