7
English
• After knocking out the knockout, it is recommended to apply repair
paint to the edge and the surrounding end surfaces to prevent rust-
ing.
(Refer to figure 18)
1.
Bottom frame
2.
Field piping
<Precautions when connecting pipes>
•
PleaserefertotheTable1forthedimensionsforprocessingflares.
•
Whenconnectingtheflarenut,coattheflarebothinsideandoutside
with refrigerating unit oil and initially tighten by hand 3 or 4 turns
beforetighteningfirmly.
• Please refer to the Table 1 for the tightening torque. (Too much tight-
eningwillendupinsplittingoftheflare.)
Table 1
Pipe size
(in.)
Tightening
torque(ft·lbf)
A dimen-
sions for
processing
flares(in.)
Flareshape(in.)
φ
3/8”
(9.5mm)
24.1~29.4
(32.7~39.9N·m)
0.504~0.520
(12.8~13.2mm)
A
45
°± 2
°
90
°± 2
°
R0.016~0.031
(0.4~0.8 mm)
φ
5/8”
(15.9mm)
45.6~55.6
(61.8~75.4N·m)
0.760~0.776
(19.3~19.7mm)
Refrigerant oil
• After all the piping has been connected, use nitrogen to perform a
gas leak check.
Precautions for connecting pipes
•
Becarefulnottoletthefieldpipingcomeintocontactwiththecom
-
pressor terminal cover.
Adjust the height of the insulation material on liquid pipe when it has
the possibility of getting in contact with the terminal. Also make sure
thatthefieldpipingdoesnottouchthemountingboltofthecompres
-
sor.
(Refer to figure 19)
1.
Compressor
2.
Corking, etc.
3.
Insulation material
4.
Bolts
5.
Field piping
•
If installing the outdoor unit higher than the indoor unit, caulk the
space around insulation and tubes because condensation on the
check valve can seep through to the indoor unit side.
[Preventing foreign objects from entering]
• Plug the pipe through-holes with putty or insulating material (pro
curedlocally)tostopupallgaps,asshowninfigure20.(Figure20
indicatestheforwardcase.Dothesameincaseofotherdirections.)
Insects or small animals entering the outdoor unit may cause a short
in the control box.
(Refer to figure 20)
1.
Putty or insulating material
2.
(fieldsupply)
6-6
Thermal insulation of piping
•
Insulatethefieldpiping(liquidandgas-side).(Notinsulatingthem
maycauseleaking.)
• The insulation dimension is recommended as following:
Ambienttemperature:86°F(30°C),
humidity : Below 80% RH
Ambienttemperature:86°F(30°C),
humidity : 80% RH and above
Minimum thickness : 9/16 inch
(15mm)
Minimum thickness : 3/4 inch
(20mm)
•
Whenusingcommercialcopperpipesandfittings,observethefollowing:
a)Insulationofpipesshouldbedoneafterperformingairtighttest
and vacuum drying.
b)Heattransferrate:0.024to0.030BTU/fth°F(0.041to0.052W/Mk
(0.035to0.045kcal/mh°C))
c)
Be sure to use insulation that is designed for use with HVAC Sys-
tems.
d)Thehighesttemperaturethatthegas-sidepipingcanreachis
around248°F(120°C),sobesuretouseinsulatingmaterialwhich
issufficientlyresistanttothistemperature.
CAUTION
For local insulation, be sure to insulate all the way to the pipe con-
nections inside the unit.
Exposed piping may cause leaks or burns on contact.
6-7
Air tight test and vacuum drying
After doing the piping, perform the following inspections.
Air tight test
Besuretousenitrogengas.(Seethefigure(“Stopvalveoperationpro
-
cedure”)forthelocationoftheserviceport.)
[Procedure]
Pressurizefromtheliquidpipesandgaspipesto550psi(3.8MPa)
(andnotabove550psi(3.8MPa)).Ifthereisnotpressuredropoverthe
next 24 hours, the equipment has passed the test.
Ifthepressuredrops,checkforleakagepositions.(Confirmthatthereis
noleakage,thenreleasenitrogen.)
IfaFTQindoorunitisused,onlypressurizeto450psi(3.1MPa).
Vacuum drying
Useavacuumpumpthatcancreateavacuumdowntoatleast
500 microns.
[Procedure]
Operate the vacuum pump for
at least 2 hours
from
both the liquid and
gas pipes
and decrease the pressure to at least 500 microns.
Leave at below 500 microns for at least 1 hour and make sure that the
vacuum gauge does not rise. (If it does rise, there is either still moisture
inthesystemoraleak.)
Cases where moisture might enter the piping
(i.e., if doing work
during the rainy season, if the actual work takes long enough that con-
densation may form on the inside of the pipes, if rain might enter the
pipesduringwork,etc.)
After performing the vacuum drying for 2 hours, pressurize to 7.2 psi
(0.05MPa)(i.e.,vacuumbreakdown)withnitrogengas,thendepressur
-
ize down to at least 500 microns a for an hour using the vacuum pump
(vacuumdrying).(Ifthepressuredoesnotreachatleast500microns
even after depressurizing for at least 2 hours, repeat the vacuum break-
down-vacuumdryingprocess.)Leaveasavacuumfor1hourafterthat,
and make sure the vacuum gauge does not rise.
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