Airwell YUDA060, Service Manual

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The air tightness test adopts nitrogen tank to give pressure according to the pipe connection mode as the following figure
shown.
The gas and liquid valve are all in close state. In order to prevent the nitrogen entering the circulation system of outdoor
unit, tighten the valve rod before giving pressure (both gas and liquid valve rods).
In 1) to 3) steps, if the pressure drops, check the leakage in each joint by listening, touching and using soap water etc.
to identify the leaking point. After confirming the leaking point, welding it again or tighten the nut tightly again.
Checking the leaking point
1) Pressurize for over 3 minutes at 0.3MPa (3.0 kg/cm
2
g).
2) Pressurize for over 3 minutes at 1.5MPa (15 kg/cm
2
g). A large
leakage will be found.
3) Pressurize for about 24 hours at 3.0MPa (30 kg/cm
2
g). A small
leakage will be found.
Installation Procedure
When the total length (L) of the two indoor units' connecting pipe is less than 5m, it is unnecessary to charge additional
refrigerant.
If the connecting pipe (L) exceeds 5m, it shall charge M(g) additional refrigerant per meter.
That is: Refrigerant charging amount = (L-5m) x 45 (g/m)
Air Tightness Test
When pressurizing for 24 hours, a variation of 1 C in the ambient temperature will cause a variation of 0.01MPa(0.1kg/cm
2
g)
in pressure. It shall be corrected during test.
Check if the pressure drops
If the pressure does not drop, then pass.
If the pressure drops, then please check the leaking point.
Cylinder pressure gauge
Cylinder of nitrogern
Line pressure gauge
Tubing bring brazed
Sweat joint
Large slip-on connector
Service hose
Additional Refrigerant Charge
Outdoor
Completely tightened
Completely tightened
Flare part
Outdoor units
Manhole
Discharging valve
stop valve totally closed
(Gas side)
Low pressure piezometer
High pressure piezometer
Meter separator
Dropping valve
stop valve totally closed
(Liquid side)
Nitrogen tank
VL VH
Indoor units
Indoor
Flare part
After finishing connection of refrigerant pipe, it shall perform air tightness test.
Only in COOLING operation can charge the additional refrigerant.
When charging, the refrigerant shall be charged from the charging nozzle of low pressure valve.
Be carefull when charging refrigerant, do not let the air mix into the system, and must charge the additional refrigerant
in liquid state.
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