14  DRAIN PIPING
Perfom the drain piping work after connecting the refrigerant 
pipes and attaching insulations.
! DANGER
Do not insert the drain pipe for the indoor unit to the drainage trench 
where corrosive gases occur. Poisonous gases ow into the room, 
so that may cause the poisoning.
? NOTE
•  Do not create an upper-slope or rise for the drain piping, since drain 
water can ow back to the indoor unit and leakage into the room will 
occur when the system 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 units.
•  After  performing  drain  piping  work  and  electrical  wiring,  check  to 
ensure that water ows smoothly as in the following procedure.
•  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.
1  Connecting direction of drain pipe: the standard direction of 
drain piping connection is right side as viewed from front. 
However, it can be performed from the left side when it is 
required due to building construction.
Left side
Right side  
(refrigerant pipe 
connection)
For left side drain piping
Cord clamp
Drain pan
Insulation
Drain plug
Remove the drain plug.
Left side
Right side
Insert the drain plug into the 
drain boss by using a driver.
Driver
Drain plug
Drain boss
Wrap the insulation around the 
drain pipe connection.
Drain plug
Silicon sealant
2  Connecting drain hose.
a.  Insert the hose into the hose clamp.
b.  Push the drain hose onto the drain boss until the hose 
reaches the end of drain pan. (If the drain hose is not 
inserted completely, it causes water leakage.)
c.  Tighten the screw for hose clamp to face the screw part 
downward as shown in the gure below to prevent dew 
drop.
d.  Wrap the insulation (accessory) around the hose clamp 
to cover drain hose, drain pan, hose clamp without gap. 
(If there is gap, dew drop may occur.)
DRAIN PIPING
PMML0551 rev.4 - 07/2023 - A10762310A
21
EN