Fujitsu AUU7RLF Design & Technical Manual page 177

Condition
When inside When the indoor unit is installed where the inside of
the ceiling is the ceiling is 30°C (86°F) RH80% or greater, the dew
high point temperature of the outer perimeter may
temperature become higher than the cabinet surface temperature
and high and moisture will condense on the surface of the
humidity. cabinet and water drops may fall inside the room.
→Refer to Fig. A.
In addition, the humidity may vary considerably the
same as when the inside of the ceiling is close to
hermetically sealed and used as the outside air
intake path.
Moist air curve
Work method when reinforcing the heat insulation
of on-site piping
Slit of heat insulating
material facing
upward
Covered gas
pipe (heat
insulation
strengthened)
Heat insulating
material (procured at
the site)
Contents
Condition which
requires addition
of outside heat
insulation
Relative humidity 80%
Dry bulb temperature 30°C (86°F)
Fig. A
Heat insulation
reinforcement material
Flare connection
(procured at the site)
Small exposed part
Binding material
of copper pipe is
desirable.
Fig. B
- 171 -
Countermeasures (Reference)
1. Add heat insulating material to
the outside of the indoor unit
cabinet.
*Regarding the cassette
type, use of optional High
humidity correspondence
kit is recommended.
2. Strengthen the heat insulating
material of the refrigerant
piping and drain piping too.
→Refer to Fig. B.
3. When the humidity inside the
ceiling changes considerably,
install a ventilation port.
To indoor unit
Fit tightly
(purpose is to
cover the sealant)