| 摘要 |
<p>PURPOSE:To prevent the boiling of water held up in a heat exchanger on hot water supply side by a method wherein the feed back control amount for maintaining the heat exchanger on the hot water supply side at a specific temp. at the time of additional heating is computed, a burner which is located near a temp. sensor and burns always is selected by the foregoing control amount and initial heating amount and a proportional valve is controlled. CONSTITUTION:At the time of starting additional heating, a first opening and closing valve control means 107 opens a first opening and closing valve 21 by the combustion start requiring signal from a means 101 for determining whether or not combustion is required and a feed forward computing means 102 computes initial heating amount F0 based on bathtub return hot water temp. Tf. Heating amount F is computed by a heating amount control means 104 and a burner which is located near a temp. sensor and burns always is selected by a heating part selecting means 105 to control the corresponding opening and closing valves 22 and 23. Also, a proportional valve control means 110 controls the opening degree of a proportional valve 30 according to the heating amount F. A feed back computing means 104 computes feed back control amount FB from a preset heat-exchanging temp. valve TZS and a heat-exchanging temp. TZ and outputs the computed result into the heating amount control means 104.</p> |
