WATER HEATER SOLENOID PILOT OPERATED TEMPERATURE AND/OR PRESSURE CONTROL VALVE

摘要

Hot water heater provides water at two preset temperatures (e.g. 50 DEG C and 80 DEG C) each at a different outlet. Controller (96) activates pilot solenoid (electromagnetic) valves (85, 89) of pressure actuated (diaphragm) flow control valve (102) to mix cold water with hot water from heat exchanger (51) at the higher temp. When flow is detected in the low temp. outlet by a sensor the same valve (102) provides water at the antiscald temp. Temperature sensor (95) provides feedback for accurate temperature control. Tempered water flow rate is controlled by another pressure actuated flow control valve (101) having pilot solenoid valves (93, 94), logic controller (96) and feedback from flowmeter (81); to e.g. compensate for a reduction in combustion gas pressure. Both solenoids (93, 94) may be opened when valve (101) controls temperature whereby bypass cold water mixes with hot water at venturi (76). Spring (70) and venturi (76) increase sensitivity. Computer controller also controls rate of gas flow dependent on water demand, fan formixing gas and air using e.g. oxygen sensor in flue and a display.