| 摘要 |
PROBLEM TO BE SOLVED: To save a draining amount of a fluid for cooling a heating unit by a drain valve by shortening a waiting time up to a start of controlling a temperature drop of an outlet temperature when a temperature drop request of the outlet temperature is set. SOLUTION: A fluid heater comprises the drain valve 60 provided before a variable valve 50. Thus, when a set temperature is changed, for example, from 35 deg.C to a lower temperature Rt, ramp heating of heating units 10a, 10b are stopped, cooling fluid flowing to the units 10a, 10b is made to start draining via a drain tube 60. Further, independently from this, a mixing ratio of the fluid (fluid temperature = Rt) flowing from a bypass tube P3 to the fluid (fluid temperature > Rt) flowing from a discharge tube P2 at the valve 50 is gradually increased, and a control for lowering the temperature (output temperature) of the mixed fluid flowing from the valve 50 is started.
|
