DRAIN PIPING
PMML0385 rev.2 - 12/2018
13
EN
5  DRAIN PIPING
5.1  GENERAL
? NOTE
•  Install drainage in accordance with national and local codes.
•  If there is excessive clearance between the drain pipe connection and 
the drain hose, add a sealing material between both parts in order to 
t and not deform the drain hose.
! CAUTION
•  Do not create an upper-slope or rise for the drain piping, since drain 
water will  ow  back to the  unit  and leakage to  the  room will occur 
when the unit operation is stopped.
•  Do not connect the drain pipe with sanitary or sewage piping or any 
other drainage piping.
•  When the common drain piping is connected with other indoor units, 
the connected position of each indoor unit must be higher than the 
common  piping.  The  pipe  size  of  the  common  drain  pipe  must  be 
large enough according to the unit size and number of unit.
Common drain piping
1/25~1/100 Down Slope
•  Drain piping will require insulating if the drain is installed in a location 
where condensation forming on the outside of drain pipe may drop 
and cause damage. The insulation for the drain pipe must be selected 
to insure vapor sealing and prevent condensation forming.
•  Drain trap should be installed next to indoor unit. This trap must be 
designed  to  good  practice  and  be  checked    with  water  (charged) 
and tested  for  correct ow.  Do not tie  or  clamp the drain  pipe and 
refrigerant pipe together.
After performing drain piping work and electrical wiring, check to 
ensure that water ows smoothly as in the following procedure:
 
 Checking with drain-up mechanism and oat 
switch
 - Switch ON the power supply.
 - Pour approximately 1.8 liters of water into the drain pan. 
Then oat switch stops the system automatically. In this 
operations the drain pump does not stops.
 - Check to ensure that the water ows smoothly or whether 
no water leakage occurs.  When water cannot be found 
at the end of the drain piping, pour another approximately 
1.8 liters of water into the drain pan.
 - Switch OFF the power supply after.
? NOTE
Pay attention to the thickness of the insulation when the left side piping is 
performed. If it is too thick, piping can not be installed in the unit.
5.2  DRAIN PIPE CONNECTION
1  Prepare a polyvinyl chloride pipe with a 32mm outer 
diameter.
2  Fasten the tubing to the drain hose with an adhesive and 
the clamp. The drain piping must be performed with a down-
slope pitch of 1/25 to 1/100.
Gradient of Drain piping
Max.  
850mm
1/25~1/100  
down slope
3  Insulate the drain pipe after connecting the drain hose. 
Insulation (eld-supplied)
Side Unit
1/25~1/100 
down slope
Polyvinyl chloride tube 
(eld-supplied)
Clamp
Drain 
piping