Drainage pipe installation 
Installation  225 
Branch pipe
Water flow
Water flow
Keep a certain degree
Branch pipe
Gas
Gas
Main pipe
Main pipe
 
  The correct installation will not cause converse water flow and the slope of the branch pipes can be 
adjusted freely 
  The false installation will cause converse water flow and the slope of the branch pipe can not be 
adjusted. 
6.2.6  Water storage pipe setting 
  If the indoor unit has high extra static pressure and without water pump to elevate the condensate water, 
such as high extra static pressure duct unit , the water storage pipe should be set to avoid converse flow 
or blow water phenomena. 
Indoor
 
unit
More than 50mm
More than 25mm
Plug
Water storage pipe
 
6.2.7  Lifting pipe setting of indoor unit with water pump 
  The length of lifting pipe should not exceed the pump head of indoor unit water pump. 
Pump head of big four way cassette: 750mm 
Pump head of compact four way cassette: 500mm 
  The drainage pipe should be set down inclined after the lifting pipe immediately to avoid wrong 
operation of water level switch. 
  Refer the following picture for installation reference.   
Flexible pipe 300mm
Hanger
A
A:Length of horizontal pipe
≤
150mm
B: Lift height
≤
the pump head of water pump
Down incline pipe
B
 
6.2.8  Blowhole setting 
  For the concentrated drainage pipe system, there should design a blowhole at the highest point of main 
pipe to ensure the condensate water discharge smoothly.