Johnson Controls York YDVC028 - Air Tight Test Procedure; Piping Insulation

VRF Air-Conditioner IOM
5
Pipe Diameter
mm (inch)
Further
tightening angle
Recommended arm
length of toll
∮ 6.35(1/4") 60 °～ 90 ° ～ 150mm
∮ 9.53(3/8") 60 °～ 90 ° ～ 200mm
∮ 12.7(1/2") 45 °～ 75 ° ～ 250mm
∮ 15.88(5/8") 45 °～ 75 ° ～ 300mm
∮ 19.05(3/4") 30 °～ 60 ° ～ 400mm
∮ 22.23(7/8") 30 °～ 60 ° ～ 400mm
Over tightening may damage the flare and cause
leakage.
5.2 AIR TIGHT TEST
 Air tight test should be done after the piping
connection completed.
 Operation method:
(a) Fill in dry nitrogen into the refrigerant piping
and let the pressure slowly rise to 4.3MPa.
(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 4.3MPa.
(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.
 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
 
+
∆ = × −
 
+
 
2correction
P P P= − ∆
P∆
— Pressure correction value (Pa)
correction
P
— the correced pressure value (Pa)
1
P
— 1
st
record pressure (Pa)
2
P
— 2
nd
record pressure (Pa)
1
t
— 1
st
record temperature (°C)
1
t
—2
nd
record temperature (°C)
 Do not connect indoor units with outdoor units
during the air test process. Otherwise, it may result
in nitrogen gas emtering into the outdoor unit.
5.3 Insulate the piping
 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
polythylene materials.
 Be sure to insulate the field piping all the way to
the piping connection inside the unit. Any exposed
piping may casue condensate water or being
scalded if touched.
6 DRAIN PIPING WORK
 YDVC series indoor unit drain pipe is the free
drainage.
 Be sure the drain pipe works well and smothly
before making the duct connection. (It is not easy
to check the drain pipe when the duct has been
connected.)
6.1 Install the drain pipe
 Make sure the drain works properly.
 Diameter of the drain pipe should be larger than or
equal to the one of the connecting pipe. (drain pipe
connection diameter of indoor unit is Ф20)
 Make a water trap on the drain pipe outlet from
indoor unit. The water trap should meet below
requirements. (A, B ≥ 50mm)
 If central drain pipe has been used, keep the drain
pipe short and sloping downwards at a gradient of
at least 2/100 to prevent air pockets from forming.
(Refer to Fig. 6)
Fig. 6 Central Drain Pipe
 Select central drain pipe of proper size according to
the total capacity of the connected unit.
(a) The parts of drain pan outlet should be well
insulated to avoid condensate water
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CAUTION
CAUTION