Hydronic heating water temperature control system

Abstract

A three-way modulated diverting valve is provided in the return line to the boiler of a hydronic heating system between the heating loop return and the boiler return, the valve having its input from the heating loop return, one output to the boiler return and the second output to the heating loop supply, so that the valve diverts some of the cooler return water to the boiler hot supply water, diluting the supply water to reduce the temperature of supply water that feeds the heating loop; and the valve is modulated by a feedback signal representative of the temperature of the diluted supply water. In a preferred embodiment, the feedback modulation is accomplished using a non-electric thermostatic actuator head that drives the valve stem and is controlled by a capillary temperature sensor, the sensor bulb being immersed in the diluted supply water or clamped to the supply line next to the heating loop supply so that it is at the temperature of the diluted supply water. In operation, capillary fluid in the bulb expands with temperature applying a pressure force through the capillary to the actuator head which drives the valve stem, and so the diverting valve is modulated to increase or decrease the flow of return water to dilute the supply water as necessary to maintain the diluted supply water temperature at a predetermined value.

Dependencies are inferred from the claim text.