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CAUTION
Pressured nitrogen (3.9MPa (44kgf/cm
be used in the airtight test.
DO NOT pressure to the stop valve directly.(See Fig.5-8)
The airtight test should never use any oxygen,flammable gas
or poisonous gas.
Wrap the low pressure valve with a wet cloth for protection
when welding.
In case of damage, the holdup time shouldn't be too long.
5.8 Air Purge with Vacuum Pump
1. Use the vacuum pump with the relative vacuum degree of
-0.1MPa, vacuum-pump efficiency of 40L/min
2. Outdoor unit needn't to be vacuumized. Do not open liquid/gas
side stop valves of the outdoor unit.
3. Be sure when vacuum pump works for more than 2 hours, the
relative vacuum degree is under -0.1MPa. If the degree is still
under -0.1MPa for more than 3 hours, it demonstrate there's
moistureor leakage. Check the pump.
Connect to vacuum pump
Operate vacuum pump(more than
2 hours)
Keep the vacuum pump operating for
another 20-60 minutes after the relative
vacuum pump reaches -0.1MPa
Vacuum pump stops
Vacuum lay up(more than 1 hour)
CAUTION
Do not mixedly use tools used for different refriferant, tools and
measuring instrument that directly contact refriferant.
DO NOT use refriferant gas to air discharge.
When vacuum degree can't reach -0.1MPa, consider if it leaks.
If no leakage, please keep the vacuum pump working for
another 1 to 2 hours.
5.9 Outdoor unit stop valve
Outdoor unit stop valve
1. Before using stop valve, get familiar with every part of the valve,
as shown in Fig.4-10. The stop valve is closed when leaving the
factory.
2. Please use a proper tool. Because the stop valve in this unit is
not a flare-seal type, if dismantling forcibly, it may cause valve
damage. Please use hosepipe to fill in when maintenance.
3. When cooling in the outside in a low temperature, operation
pressure will be low. Use silicone encapsulant to seal in case of
freezing of flare nut of stop valve gas side.
4. Make sure if there is refrigerant leakage after fastening the
bonnet.
Operational approach of closing the valve
Prepare a hexagonal wrench(specification 6mm)
2
) for R410A] should
1. Close the valve of pressure
gauge.
2. Disconnect the connection
of pressure gauge and
vacuum pump.
3. Stop vacuum pump.
Fig.5-9
11
Open approach:
1. Insert a hexagonal wrench into the valve rod and spin
anticlockwise.
2. When the valve rod can't be spinned any more, the valve is
open.
Close approach:
Insert a hexagonal wrench into the valve rod and spin clockwise.
Maintenance port
Valve rod
Bonnet
Bonnet caution
Tightening the bonnet after valve operation.
Main tenance port caution
Please operate with a filling hosepipe with a compression bar.
Tightening the valve after operating.
Stop valve specification
Model
33.5kW/40kW
Liquid side stop valve
Gas side stop valve
Opening direction
Liquid side
5.10 Leakage inspection
Inspect each joint to check if it leaks by using a leak detector
or suds.(Fig.5-12)
NOTE: A liquid side stop valve
B gas side stop valve
C and D are the joint of the indoor unit connecting pipe.
A
Outdoor unit checking points
5.11 Heat Insulation
Do the heat insulation to the pipes of air side and liquid side
separately. The temperature of the pipes of air side and liquid
side when cooling, for avoiding condensation please do the
heat insulation fully.(Fig.5-13)
1. The air side pipe should use closed cell foamed insulation
material, which the fire-retardant is B1 grade and the heat
resistance over 120°C.
2. When the external diameter of copper pipe≤Φ12.7mm, the
thickness of the insulating layer at least more than 15mm;
When the external diameter of copper pipe≥Φ15.9mm, the
thickness of the insulating layer at least more than 20mm.
Table 5-12
45kW
Φ12.7
Φ12.7
Φ22.2
Φ25.4
Opening direction
Gas side
Fig.5-11
Indoor unit
checking point
D
B
Fig.5-12
V.2
Fig.5-10
C
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