Fujitsu Airstage J-II Series Design & Technical Manual page 584

2-4. SELECTION OF PIPE HEAT INSULATING MATERIAL
● Always insulate the refrigerant pipe to prevent condensation and water droplets by the
„
refrigerant pipe.
● Decide the thickness of the heat insulating material by referring to the recommended
„
minimum thickness in Table 1. (For installation condition T=90°F DB (32°C DB),
humidity≤70%, humidity≤75%, humidity≤80%, humidity≤85%)
● When the outdoor unit is installed in a higher position than the indoor unit, fill the connecting
„
part gap with putty, etc. to prevent the dew condensation water of the valve of the outdoor
unit from flowing to the indoors from the gap between the pipe and the heat insulating
material.
● Liquid pipe and gas pipe should be completely insulated with same specification.
„
● In case not to insulate and not to seal refrigerant pipe completely, it will become the cause of
„
water leak.
● Table1 Size of refrigerant pipe and recommended minimum thickness of heat insulating
„
material
(In case a heat insulating material which thermal conductivity is equal to or less than 0.040 W/(m·k)
is used. )
Relative humidity
Refrigerant
pipe
Outside
diameter [in.
(mm)]
● When an ambient temperature and relative humidity exceed 90°F DB (32°C DB)and 85%
„
respectively, strengthen heat insulation of refrigerant pipe. If necessary put a heat insulation
on indoor unit casing. When not strengthening heat insulation of refrigerant pipe, the
surface of the heat insulation may be dewed.
● Since gas pipe becomes high temperature at heating operation for heatpump type, select
„
the heat insulating material which heat-resistant temperature is 248°F (120°C) or more.
Gas pipe
Heat insulation
● Make sure that pipe is covered completely by the heat insulation,not exploding to air.
„
Inadequate heat insulation may cause condensation.
● Do not cover heat insulation gas and liquid pipes together as above figure. It may cause
„
condensation and capacity drop by heat loss.
Recommended minimum thickness for heat
insulating material [in. (mm)]
≤70%
1/4" (6.35) 5/16" (8) 13/32" (10)
3/8" (9.52) 11/32" (9)
1/2" (12.70) 13/32" (10) 15/32" (12) 19/32" (15)
5/8" (15.88) 13/32" (10) 15/32" (12)
3/4" (19.05) 13/32" (10)
Connection cable
Finishing tape
Liquid pipe
≤75% ≤80%
1/2" (13)
7/16" (11) 9/16" (14) 23/32" (18)
5/8" (16)
1/2" (13) 5/8" (16)
Gas pipe
Liquid pipe
Heat insulation
- (06 - 20) -
≤85%
21/32" (17)
3/4" (19)
25/32" (20)
13/16" (21)