Gas water heater and control method thereof

The invention discloses a gas water heater and a control method thereof. The gas water heater comprises a shell, a condenser, a fume exhaust pipe, a primary heat exchanger, a water outlet pipe and a condensate water return pipe, wherein the condenser is arranged in the shell; the fume exhaust pipe is arranged on the shell; the fume exhaust pipe is communicated with the interior of the condenser; the primary heat exchanger is connected with the condenser; the water outlet pipe is connected with the primary heat exchanger so as to discharge water which is subjected to heat exchange in the primary heat exchanger; one end of the condensate water return pipe is communicated with the interior of the condenser, and the other end of the condensate water return pipe is communicated with the water outlet pipe so as to convey condensate water in the condenser to the water outlet pipe. According to the gas water heater disclosed by the invention, the condensate water return pipe is arranged, so that the water in the condenser can enter into the water outlet pipe so as to be recycled, so that a special condensate water discharge structure is not needed to discharge the condensate water to a underground pipeline; furthermore, on the premise of not reducing the efficiency of the gas water heater, no condensate water emission of the gas water heater can be realized.