Haier AB072MRERA Service Manual page 284

7. Cautions in Installation of Air Return Pipe & Exhaust Pipe
It is recommended to use the blast pipes, which can be anti-condensation
and absorb sound. (purchased at local shops)
Complete the installation of the blast pipes before fitting up the suspended
ceiling.
Heat insulation should be made for the blast pipes.
The special exhaust port should be arranged at the place where the air is
distributed evenly.
An inspection hole should be left on the surface of the ceiling for future
maintenance.
8. Examples for Bad Installation
The unit is not equipped with the air return pipe and the inner side of the suspending ceiling is used as the blast
pipe, causing the humidity increasing due to irregular air mass, strong wind or sunlight from the outside world.
There might be condensate dropping down at the outer side of the blast pipe. The humidity is high, even if the
inner side of the suspended ceiling isn't used as a blast pipe in new concrete buildings. At this time, the whole body
should use the thermo wool for heat preservation (the thermo wool can be packed with a steel wire).
It is operated under the conditions beyond the limits, leading to the overload of the compressor.
Affected by the capacity of the exhaust fan, and the strong wind and wind direction in the outer flue, when the
blowing quantity of the air conditioner exceeds the limits, the drained water of the heat exchanger will overflow,
causing water leakage.
9. Refrigerant Pipe
Pipe Length & Height Difference
Please refer to the attached manual of outdoor units.
Piping Materials & Heat Insulating Materials
As to prevent condensation, heat insulating treatment should be
performed. The heat insulating treatment for piping should be done
respectively.
Exhaust fan
Example of bad installation
276
S
Air
Air
Hard PVC tube
Piping Material
VP31.5mm (inner bore)
Heat Insulating Vesicant polythene
Material thickness: over 7mm
Blast pipe