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Refrigerant Pipe Installation
(1) After the airtight test, discharge nitrogen gas.
Connect a gauge manifold to the service ports at liquid, gas and balance sides, and
connect a vacuum pump as shown in the following figure.
Be sure to perform vacuuming at liquid, gas, and balance sides.
Detailed drawing of packed valve
{
To gauge manifold
Liquid-side
service port
Liquid-side
packed valve
To main
Balance
unit
service port
Piping
Balance
at site
packed valve
To main unit
Piping at site
(2) Use a vacuum pump with a large displacement so that the vacuum will achieve
below –755mmHg.
(3) Perform vacuuming for 2 or 3 hours, though time requirement differs due to pipe length.
During this time, check that all packed valves at liquid, gas, and balance sides are fully
closed.
(4) If vacuuming does not reach –755mmHg or below even after vacuuming for 2 hours or
more, perform vacuuming for a futher hour.
If vacuuming still does not reach –755mmHg after 3 hours, check for leakage.
(5) When vacuuming reaches –755mmHg or below after vacuuming, fully close valves.
Close V
and V
on the gauge manifold fully, stop the vacuum pump. After 1 hour check
L
H
the vacuum gauge reading has not change. If there is a change, there may be a leak.
Check for leak.
(6) After the above procedure of vacuuming has completed, replace the vacuum pump with a
refrigerant cylinder, and advance to additional refrigerant charging work.
Vacuuming
Connected to Indoor Unit
Packed valve fully
Main pipe
closed (gas side)
Brazed
Gas-side
service port
Gas-side
Fully
packed valve
closed
To main
unit
Fully
closed
Piping
at site
Connected to other fixed-speed Outdoor Unit
107
Low-
pressure
gauge
V
V
L
Inverter Outdoor Unit
Service
port
Service port
Packed valve fully
Vacuum pump
closed (liquid side)
Packed valve fully
closed (balance)
High-
pressure
gauge
Gauge
H
manifold
17
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