YORK VRF Air-Conditioner IOM
5
z
Do not use flux when brazing refrigerant piping.
Therefore, use the phosphor copper brazing filler
metal (BCuP) which does not require flux.
If chlorine based flux is used, it will cause pipe
corrosion and contamination of refrigerant oil
6.1 Connect the piping
z
Be sure to use both a spanner and torque wrench
together, as shown in Fig. 6, when connecting or
disconnecting pipes to/from the unit.
Fig. 6 Piping Connection
z
Refer to Table 1 for the tightening torque.
Table 1
Pipe Diameter
mm (inch)
Tightening Torque
(N
g
m)
Ħ
6.35(1/4") 14
̚
17
Ħ
9.53(3/8") 32.5
̚
40
Ħ
12.7(1/2") 49.5
̚
60
Ħ
15.88(5/8") 62
̚
75
Ħ
19.05(3/4") 80
̚
95
Ħ
22.23(7/8") 100
̚
115
z
If no torque wrench is available, please follow the
below method to do the installation.
Using a wrench to tighten flare nuts causes the
tightening torque to suddenly grow much tighter
after a certain point. From that point, tighten the
nut further by the appropriate angle listed in Table
2.
Table 2
Pipe Diameter
mm (inch)
Further tightening
angle
Recommended arm length
of toll
Ħ
6.35(1/4") 60
e̚
90
e
̚
150mm
Ħ
9.53(3/8") 60
e̚
90
e
̚
200mm
Ħ
12.7(1/2") 45
e̚
75
e
̚
250mm
Ħ
15.88(5/8") 45
e̚
75
e
̚
300mm
Ħ
19.05(3/4") 30
e̚
60
e
̚
400mm
Ħ
22.23(7/8") 30
e̚
60
e
̚
400mm
Over tightening may damage the flare and cause
leakage.
6.2 AIR TIGHT TEST
z
Air tight test should be done after the piping
connection completed.
z
Operation method:
(a) Fill in dry nitrogen into the refrigerant piping
and let the pressure slowly rise to 4.15MPa.
(b) The specified pressure should be maintained
for 10 minutes, and then soapy water or other
foaming agent are applied to the connection
positions, such as brazing seams, screwed
joints ,etc. for leakage detection.
(c) If it has leakage, then tighten or braze the
leakage point.
(d) After it has been confirmed that the piping
does not leak, the dwelling test should be
performed. Fill in the dry nitrogen again and
let the pressure slowly rise to 4.15MPa.
(e) The pressure needs to be maintained for 6
hours and then record the pressure value
through the manometer. 24 hours later, record
the pressure again.
(f) No pressure drop after 24 hours means it has
no leakage. Otherwise, the leaking point must
be found and mended. Then repeat the above
(d) and (e) steps.
z
Gas pressure is relevant to ambient temperature.
So temperature should be considered when judging
the pressure variation. The relationship of pressure
and temperature is shown below.
2
1
1
273 1
273
t
P P
t
§
·
' u
¨
¸
©
¹
2
correction
P
P
P
'
P
'
— Pressure correction value (bar)
correction
P
— the correced pressure value (bar)
1
P
— 1
st
2
P
record pressure (bar)
— 2
nd
1
t
record pressure (bar)
— 1
st
1
t
record temperature (°C)
—2
nd
record temperature (°C)
z
Do not connect indoor units with outdoor units in
during the air test process. Otherwise, it may result
in nitrogen gas emtering into the outdoor unit.
6.3 Insulate the piping
z
After checking it has no leakage, be sure to insulate
the connection parts of both liquid and and gas
pipe with sufficient thickness heat-resistant
NO
TE
NO
TE
CAUTION
CAUTION
