Vertical/Horizontal Air Handler Unit Drain Information
Note:
Install a field-supplied external condensate pan underneath the entire
vertical air handler unit to avoid damage due to condensate overflow.
Vertical / Horizontal Air Handler units have a gravity drain.
• Avoid blocking filter access panel when connecting drain lines.
• An additional external condensate line should run from the unit
into the pan.
• The entire condensate line should be drained from the external
condensate pan.
• Point the drain hose downward for easy drain flow.
Do not use pipe joint connection or PVC/CPVC for the unit
•
drain line connection. Use Teflon® tape.
Install the Condensation Drain Pipe
• Drain piping must slope down or flow may reverse back to unit.
• During drain piping connection, be careful not to exert extra force
on the drain port on the indoor unit.
• Refer to Table 17 for drain pipe sizing.
• Use polyvinyl chloride pipe.
• Install insulation on the drain piping.
• Use polyethylene foam greater than 5/16 inch thick for insulation.
1. Refer to Figure 30 and plan the drain pipe routing so that the pipe
will slope downward from the indoor unit to its end drain location.
Figure 30: Drain Piping Slope.
Pipe clamp
Indoor unit
Maintenance
drain port
2. Connect the provided flexible drain pipe to the main drain pipe.
3. Pour water into the flexible pipe as shown in Figure 33 to test for
leaks. Repair leaks if necessary.
4. Route the flexible drain pipe to the indoor unit and connect the
flexible drain pipe to the drain port of the indoor unit.
5. Install field-supplied thermal insulation on the flexible drain pipe
and position snugly against indoor unit.
Figure 32: Do Not Sharply Bend Drain Pipe.
Upward
routing
not allowed
Flexible drain hose
Due to our policy of continuous product innovation, some specifications may change without notification.
©LG Electronics U.S.A., Inc., Englewood Cliffs, NJ. All rights reserved. "LG" is a registered trademark of LG Corp.
CONDENSATE PIPING
Figure 28: Vertical / Horizontal Air Handler Unit Drain Piping System.
Figure 29: Vertical / Horizontal Air Handler Unit U-Trap Specifications.
• Install the U-Trap to prevent leaks
caused by blocking the intake air filter.
Applied U-Trap Dimensions
A ≥ 2-9/16 inch
B ≥ 2C
C ≥ 2 x SP
SP = External Pressure
(in. WG)
C
Ex) External Pressure
= 0.4 in. WG
A ≥ 2-9/16 inches
A
B ≥ 1-7/12 inches
C ≥ 13/16 inches
Figure 31: Properly Insulating the Drainage Piping.
Insulation
Insulation
Not Required
Requir ed
Figure 33: Testing the Drain Pipe.
Pour water to
test for proper
drainage and
no leaks
Drain Pump
Drain pan
3/4 inch
connector
B
U-Trap
Properly Fitting Insulation
Flexible drain hose
Main drain pipe
Drain
Glue the joint
port
Drain hose clip (provided)
45