| 摘要 |
PURPOSE:To prevent breakage of the titled device due to freezing by a method wherein the connecting port of feed water is provided with a suction valve, while the connecting port of supplying hot-water is provided with a low-temperature operating valve and a water passing circuit is provided with an automatic water extracting valve at the lowest part, in addition to an electric heater. CONSTITUTION:An antifreezing heater 1c is attached to a heat exchanger, the antifreezing heater 1e is attached to an automatic water extracting valve 12 and a bimetal switch 2 is fixed to a water stream switch 5. A water passing circuit is provided with a suction valve 10, the delivery port of supplying hot-water is provided with a low-temperature operating valve 11 and the lowest part of the water passing circuit is provided with an automatic water extracting valve 12 utilizing a diaphragm valve. When a temperature in a machine is reduced to the ON setting temperature of the bimetal switch 2, the antifreezing heaters 1a, 1b, 1c, 1d, 1e are conducted to keep the temperature of the water passing circuit. In case they are not conducted, the low-temperature operating valve 11 is opened when water temperature is reduced whereby water beings to flow through the water passing circuit in the machine and freezing is prevented. When an antifreezing water feeding cock 8 is closed and a hot-water supplying cock 9 is opened, the pressure of water in the machine is reduced and a non-return valve 13, the automatic water extracting valve 12 and the suction valve 10 are opened whereby remaining water is discharged through the automatic water extracting valve 12.
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