Heat exchanger cleaning device, cleaning method and air conditioner

The invention discloses a heat exchanger cleaning device and method and an air conditioner, the heat exchanger cleaning device comprises a reversing valve, a water pan, a spraying pipe and a power assembly, the reversing valve is used for switching a heat exchanger to be cleaned into an evaporator to generate condensate water, and the water pan is arranged below the heat exchanger to be cleaned; spraying holes with openings facing the heat exchanger to be cleaned are distributed in the spraying pipe, and the power assembly is used for pumping condensate water collected by the water pan to the spraying pipe. The heat exchanger cleaning method comprises the steps that whether a descaling instruction exists or not is judged; if yes, the descaling action is executed, the to-be-cleaned heat exchanger is switched into an evaporator, condensate water dripping from the to-be-cleaned heat exchanger is collected, and the condensate water is used for spraying and washing the to-be-cleaned heat exchanger; and if not, wai