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6.2 Pipe-work connection
Sweat connection:
•
Locate the suction & liquid pipe service valves in the compressor compartment by removing the service access
panel
Check that the service valves are tightly closed (Service Ball valves have been provided for suction and liquid
•
lines)
Wrap each valve in turn with a wet cloth prior to sweating off its associated blanking plate (Flare nut connection is
•
fitted on some of the indoor units to avoid brazing)
•
Braze the interconnecting liquid and suction pipes from the indoor unit
Pressurise the indoor unit & pipe-work again with dry nitrogen and check for any brazed joint leaks. Repair as
•
necessary but ensure the system is not under pressure prior to brazing
•
With the indoor unit pressure again released, evacuate to a vacuum pressure of 100 microns minimum
Disconnect the vacuum pump whilst retaining the system vacuum
•
•
Open the liquid line valve fully first, and then the suction line valve
Flare connection:
•
Cut the pipe with pipe cutter
Insert the flare nut into the pipe and flare the end
•
•
Refer to the following table for the dimension of flare nut spaces:
Connect the indoor unit first and then the outdoor unit.
•
Bend the refrigerant pipe in the correct way to prevent damage.
•
•
The bending angle should not exceed 90°.
The preference is to place any bends in the middle of the pipe. The larger the bending radius the
•
better, as it reduces internal pressure drop.
Do not bend pipe more than is necessary.
•
When connecting the flare nut, coat the flare both inside and outside with approved oil and
•
initially tighten by hand 3 or 4 turns before tightening firmly
Pipe Gauge
Tightening Torque
14.2 ~ 17.2 N.m
Ø 6.4
(144 ~ 176 kgf.cm)
32.7 ~ 39.9 N.cm
Ø 9.5
(333 ~ 407 kgf.cm)
49.5 ~ 60.3 N.m
Ø 12.7
(504 ~ 616 kgf.cm)
61.8 ~ 75.4 N.m
Ø 15.9
(630 ~ 770 kgf.cm)
97.2 ~ 118.6 N.m
Ø 19.0
(990 ~ 1210 kgf.cm)
Table 3 – Flare Dimensions and Flare Tightening Torque
Flare Dimensions 'A'
Minimum
Maximum
(mm)
(mm)
8.3
12.0
12.4
15.4
15.8
18.6
19.0
22.9
23.3
.
20
8.7
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