| 摘要 |
PROBLEM TO BE SOLVED: To provide a gas water heater to improve further safety. SOLUTION: A controller 9 of the gas water heater 1 predicts a supply hot water temperature T by a formula of Qg×H×η/100=ρ×(T-Ti)×W from a parameter, such as Qg being a gas flow rate (M3/s) per a unit time determined from the openings of a main gas solenoid valve 19 and a gas proportional valve 21, H being a gas heat generating rate (MJ/m3) of fuel gas,ηbeing heat efficiency (%) of fuel gas,ρbeing a water specific heat ratio (MJ/(kg. deg.C), Ti being an inflow water temperature ( deg.C) detected by an inflow water thermistor 15, W being a water flow rate (kg/s) per a unit time determined by a water sensor 13 and from the opening of a water flow control valve 33. When an absolute value of a difference between the predicted supply hot water temperature T and a supply hot water temperature To detected by a supply hot water thermistor 35 exceeds a certain value, operation of apparatuses is stopped.
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