Backflow water tank for split heat exchange type solar water heater

A backflow water tank for a split heat exchange type solar water heater comprises a backflow tank body arranged above a water tank of the solar water heater, a liquid outlet connected with a water inlet pipe of a heat exchanger in the solar water heater is arranged on a side wall of the lower part of the backflow tank body, an exhaust and liquid adding port is arranged at the top of the backflow tank body, a guide pipe is vertically arranged in the backflow tank body, the upper end of the guide pipe is connected with an outlet of a heat collector of the solar water heater, a plurality of supplement and exhaust holes are formed in the pipe wall of the guide pipe close to the top of the backflow tank body, and the total area of the supplement and exhaust holes is larger than or equal to the cross sectional area of the guide pipe. According to the backflow water tank, the guide pipe is inserted in the bottom of the tank body directly, and the supplement and exhaust holes are formed in the guide pipe, so that the