The invention relates to a condensate water prevention gas
water heater. The condensate water prevention gas
water heater comprises a shell, a
heat exchanger, a first draught fan, a vent
pipe, a second draught fan, a temperature and
humidity sensor and a temperature sensor, wherein the first draught fan is arranged at an air inlet of a
combustion chamber; the second draught fan and the temperatureand
humidity sensor are arranged close to an outlet of an air inlet
pipe; the temperature sensor is arranged on the surface of the
heat exchanger; the vent
pipe comprises the air inlet pipe and a
smoke exhaust pipe which are isolated; and a spiral blocking plate is arranged in the air inlet pipe. The invention further relates to a control method of preventing condensate water of the gas
water heater. The control method comprises the steps of calculating the
moisture content of air going into the shell, and calculating the
moisture content of
combustion products; calculating the
moisture content of
exhaust gas according to the moisture content of the air and the moisture content of the
combustion products; calculating the
dew point temperature of the
exhaust gas according to the moisture content of the
exhaust gas; and comparing the
dew point temperature of the exhaust gas with the surface temperature of the
heat exchanger, adjusting the rotating speeds of the second draught fan and the first draught fan according to the comparison result and then reducing the moisture content of the air going into the shell. Through the condensate water prevention gas water heater and the controlmethod, the
dew point temperature of the exhaust gas can be reduced, and generation of condensate water is prevented.