INSTALLATION MANUAL FOR INDOOR UNIT
Recommend to use 
The duct installation work should be finished before the fitment of ceiling.
The duct must be heat insulated.
The specific 
The surface should leave a checking meatus for checking and maintenance.
Duct
Do not use air in duct and take the ceiling inner side instead. The result is because of the irregular outer air mass, strong wind and sunshine, the humidity is increased.
There may be water drop on the outside of duct. For cement and other new constructions, even if not taking ceiling inner side as duct, the humidity will also be so high. At this time, use glass fiber to perform heat preservation to the whole. (use iron net to bind the glass fiber)
Maybe exceeding the unit operation limit (for example: when indoor dry bulb temperature is 35
C, wet bulb temperature 24
C), it may lead to overload of compressor.
Affected by the capacity of air discharging fan, the strong wind in the outer duct and wind direction, when unit air sending volume exceeds the limit, the discharged water of heat exchanger will overflow, leading to water leakage.
HDU-28H03/H, HDU-42H03/H, HDU-24H03/H specifications
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In summary, the Haier HDU-28H03/H, HDU-42H03/H, and HDU-24H03/H models combine advanced inverter technology, high energy efficiency, a wide operating temperature range, and quiet operation to deliver outstanding performance. Their smart features and eco-friendly refrigerant make them a reliable choice for those seeking comfort and efficiency in their HVAC systems.