Ventilation system with cleaning mode and method for controlling the same

A ventilation system comprising:

• a ventilator;
• and
• an outdoor unit,
• wherein the ventilator includes:
• a housing including a first intake, a second intake, a first outlet, and a second outlet,
• a plurality of dampers configured to change flow paths of air flowing through the housing,
• a first air blower configured to blow the air to the first outlet,
• a second air blower configured to blow the air to the second outlet,
• a total heat exchanger in the housing,
• a heat exchanger in the housing,
• a heat exchanger temperature sensor configured to detect temperature of the heat exchanger, and
• a processor configured to, in response to entering a heat exchanger cleaning mode:
• control the plurality of dampers, the first air blower, and the second air blower to force the air to flow into the heat exchanger,
• while the air flows into the heat exchanger, control the outdoor unit to operate to form frost on the heat exchanger, and
• control the outdoor unit to stop operating based on an operation time of the outdoor unit reaching a preset limit time or a detected temperature of the heat exchanger reaching a target temperature,
• wherein the air forced to flow into the heat exchanger is selected from one of:
• a first flow path in which outside air is drawn in through the first intake, then flows through an intake air inflow end of the total heat exchanger, then flows through the total heat exchanger, then flows through the heat exchanger, and is then discharged through the first outlet, and
• a second flow path in which room air is drawn in through the second intake, then flows into the intake air inflow end of the total heat exchanger, then flows through the total heat exchanger, then flows through the heat exchanger, and is then discharged through the first outlet.