| 摘要 |
PURPOSE: A drain apparatus with a siphon tube and a drain control technique are provided to prevent drained water in a siphon tube of a heat exchanger from flowing back into the heat exchanger. CONSTITUTION: A water supply electronic valve(15) is closed and an air vent electronic valve(18) is opened to keep an inside of a heat exchanger(1) at atmosphere pressure. A drain electronic valve(13) is opened to allow water to be drained through a siphon tube(17) installed on an outlet side header(7). A float switch(6) senses water drained into a drain plate(3) to operate a drain pump(5). Water in the siphon tube is drained through a drain auxiliary chamber(12) by negative pressure generated in the drain auxiliary chamber so that water in the heat exchanger is completely drained. The float switch is turned off to stop the drain pump and close the drain electronic valve and the air vent electronic valve when drainage of the heat exchanger is completed. An apparatus works to prevent damage of the heat exchanger due to freezing when indoor temperature drops down to sub-zero temperature while the heat exchanger is not working.
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