LMCN078HV Engineering Manual
FOUR-WAY VAHU INDOOR UNITS
Installation and Best Layout Practices
Drain Piping Specifications
• Drain piping must have downward gradient of at
least 1/50 to 1/100; to prevent reverse flow, slope
must not be straight up and down.
• Do not damage the drain port on the indoor unit
when connecting the field-supplied drain piping.
Drain Hole
Gaps Should Not Be Present
Unit
Drain Piping
(Field Supplied)
Drain Piping Insulation
(Field Supplied)
U-Trap
B
C
A
3/4-inch Connecto
r
Field-Installed U-Trap Specifications
Figure 233:Close up of Drain Piping Connection.
Figure 234:Installing the U-Trap.
To prevent leaks cause by a block in the intake air lter, install a U-Trap.
A ≥ 2-9/16 inches
B ≥ 2C
C ≥ 2 x SP
SP = External Pressure in. WG
Example:
External Pressure= 0.4 in WG
A ≥ 2-9/16 inches
B ≥ 1-7/12 inches
C ≥ 19/24 inches
Upflow Drain Horizontal-left Drain
Horizontal-left
Drain Knockout
Air filter cover
Main drain along with suitable trap.
( Field supplied trap with sufficient
depth can be used. P-traps of standard
size are not sufficient. Refer the figure
for recommended condensate trap.)
Supplementary drain
with proper trap. (field
supplied kit can be used)
Figure 235: Vertical Primary and
Secondary Drain Layout.
Figure 236: Horizontal Primary and
Secondary Drain Layout.
Refrigerant Piping Insulation
Field-installed vapor and liquid refrigerant piping lines must
be properly and completely covered in insulation (up to the
indoor unit piping connections) and must comply with federal,
state, and local requirements. Any exposed piping will gener-
ate condensate or will cause burns if touched. Insulation for
this field-installed refrigerant piping must have a minimum heat
resistance of 248°F.
If the indoor unit is installed and is operated at an extended
period in a highly humid environment (dew point tempera-
ture >73°F), however, condensate will form. To prevent this
phenomenon, install adiabatic glass wool insulation with a
thickness of 7/16 to 13/16 inches thick. Also, install glass wool
insulation on all indoor units that are located in the ceiling
plenum.
Drain Piping Insulation
Drain piping insulation must be 7/32 inches thick, minimum.
Insulating the Refrigerant and
Drain Piping
Connection for Liquid Piping
Refrigerant Piping
Insulation (Field Supplied)
Connection for Vapor Piping
Insulation Zip Tie (Field Supplied)
Refrigerant Piping Insulation (Field
Supplied)
Figure 237:Close Up of Refrigerant Piping Connection Insulation.
Gaps Should Not be Present
Overlap Piping Insulation
Refrigerant Piping Insulation (Field Supplied)
Insulation Clip (Field Supplied)
Refrigerant Piping Insulation
(Field Supplied)
Figure 238: Insulating the Refrigerant Piping and Refrigerant Piping
Connections.
Ensure all piping is insulated. Exposed piping can cause
burns if touched.
Due to our policy of continuous product innovation, some specications may change without notication.
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Multi F and Multi F MAX Indoor Unit Engineering Manual
MULTI
F
MAX
MULTI
F