Carrier CDII-184R1-0CTR4 Installation & Operation Manual page 27

6. After performing the steps above keep the Nitrogen gas flowing until the pipe cools down to
a certain extent (temperature at which pipes are touchable with hands).
7. Remove the flux completely after brazing.
Leak testing: Quarterly check joints at valves / flare connections for leaks. In case of any
leaks, repair the leak and evacuate and dehydrate the unit before charging.
After pressurizing the system, do the following:
• SOAP TEST
Apply soap solution at all flare connections and brazing point. If bubbles appear at some points,
then tighten the flare nut or braze the leaking points (after releasing the gas from the system).
No bubbles should finally appear.
• PRESSURE DECAY TEST
After soap test, note the pressure and leave the system pressurized for 30 minutes. Note the
pressure again. There should be no pressure decay, recheck for leaks, remove them and do
the pressure decay test again.
7.7 PIPE INSULATION
3
Suction lines should be insulated with a vapor proof insulation because suction lines are cold –
40°F (4.4°C) SST – and cause condensation, even in conditioned spaces.
In addition, any heat that enters the refrigerant adds to the superheat and reduces system
efficiency. Rubratex is most common form of refrigerant line insulation.
Liquid lines generally are insulated. They are warm to hot (110°F (43.3°C) for air-cooled). If
liquid lines pass through a space that is warmer than the refrigerant (i.e. the roof of a building
at roof level), or if they could be considered hot enough to pose a safety risk, then insulation
should be added. Discharge lines are generally uninsulated. They may be very hot, in excess
of 150°F (66°C), so Insulation may be warranted as a safety consideration, or if the heat loss
from the discharge gas line would be considered objectionable to the space.
1) Pipe
2) Pipe Insulation
2
3) Adhesive tape
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