! 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.
•  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.
? NOTE
Install drainage in accordance with national and local codes.
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 2.0 to 2.5 liters of water gradually into 
the drain pan, then oat switch up and drain pump start 
working automatically.
•  Check to ensure that the water ows smoothly inside the 
transparent drain pipe connection whether no water leakage 
occurs. When water cannot be found at the end of the drain 
piping, pour more water smoothly into the drain pan.
•  If the water overows from the drain pan, recheck the drain 
piping.
•  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  The position of the drain pipe connection is shown below. 
55
82
184
(mm)
2  Prepare a polyvinyl chloride pipe with a 32mm outer 
diameter.
3  Fasten the tubing to the drain hose with an adhesive and the 
factory-supplied clamp. 
28mm
20
+
5mm
Hose band (accessory)
Use vinyl chloride 
type adhesive
Tightening torque: 
3.0 - 3.5N.m
Elbow or vinyl chloride VP25 
(Field-supplied)
Vinyl tape
Drain pipe connection 
for checking drainage 
(transparent)
Drain hose 
(accessory)
Max. 300mm
4  The drain piping must be performed with a down-slope pitch 
of 1/25 to 1/100.
5  a+b+c ≤ 1100mm
b
c ≤ 50mm
Ceiling
Hose band 
(accessory)
a (Max. 300mm)
Drain hose (accessory)
Support 
part
1 to 1.5m
1/25 to 1/100
Down-slope
Max. 850mm
6  Do not apply excessive force to the Drain Pipe connection. It 
could cause a damage.
7  Do not use a bent or twisted Drain Hose. It will cause water 
leakage.
8  Insulate the drain pipe after connecting the drain hose.
Hose band (accessory)
Insulation (5T x 270 x 270) (accessory)
Wrap up the drain hose completely to 
cover the hose band
? NOTE
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.
DRAIN PIPING
PMML0547 rev.0 - 11/2020
8