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PIPING WORK AND REFRIGERANT CHARGE
Stop valve for gas pipe
(High/low pressure)
Do NOT put two wrenches
here.
Stop valve for
liquid pipe
Position both wrenches here
Air-tight test method
Connect the manifold gauge to the check joints of the liquid
line and the gas line stop valves using charging hoses with a
vacuum pump or a nitrogen cylinder. Perform the air-tight test.
Do not open the stop valves. Apply nitrogen gas pressure of
4.15MPa for FSXNSE and FSXNPE series. For checking gas
leakage, use the leak detector or forming agent. If there is any
leakage, fix the leaking part.
For checking gas leakage, do not use a forming agent which
generates ammonia. Additionally, do NOT use a household
detergent as forming agent whose components are not clear.
The recommended foaming agent for checking gas leakage is
shown below.
Procedure
Completion of
Applying
refrigerant piping
nitrogen gas
8.5 VaCUUminG
Connect a manifold gauge and vacuum pump to the check joints.
High/low pressure gas stop valve
Heat pump system
Liquid stop valve
High/low pressure gas stop valve
Heat recovery system
Low pressure gas stop valve
Liquid stop valve
8.5.1 Basic Method
If the penetration of moisture is suspected, perform "Triple
Evacuation Method" that is described in the next paragraph.
1 Vacuum until the pressure reaches 500 microns (0.5 mmHg)
or Lower for two hours.
2 After vacuum pumping work, stop the vacuum pumping and
leave the gauge for one hour.
3 Check to ensure that the pressure in the vacuum gauge
does not increase.
4 Tighten the caps of check joint according to the specified
torque after the vacuum drying work.
5 If the pressure inside the gauge does not reach 500 microns,
30
PMML0479 rev.4 - 11/2018
Stop valve for gas pipe
(Low pressure)
Flare nut
Check of pressure
decrease
Repairing of
leakage part
recommended forming agent or
equivalent
Guproflex
!
D a n G e r
Be sure to use Nitrogen Gas for air-tight test. If other gases such
as oxygen gas, acetylene gas or fluorocarbon gas are accidentally
used, it may cause an explosion or gas intoxication.
Insulation work
1 Securely insulate high/low pressure and low pressure (for
heat recovery system only) gas piping side and liquid piping
side individually. Make sure to insulate the union flare nut for
the piping connection as well.
2 Mount the piping cover equipped with the outdoor unit after
connecting the pipe. Completely seal the penetration part
at the bottom of the pipes with insulation in order to prevent
rain water from entering the conduit.
3 Cover the gap between the piping cover and pipes with
a packing (field-supplied) after the insulation work is
completed.
?
n o t e
If the gap is not covered, the unit may be damaged if snow, rain water or
animals enter the unit.
Pass
it is considered that there is gas leakage.
6 Check for any gas leakage once again.
7 If no leakage exists, it might be moisture remains inside the
pipes. Perform "Triple Evacuation Method".
8.5.2 Triple Evacuation Method
According to the following [Step 1] [Step 2] [Step 3] in order,
conduct vacuum drying work.
Step 1
1 Vacuum until the pressure reaches 2000 microns
(2.0 mmHg).
2 Pressurize with nitrogen up to 0.3 MPaG (50 PSIG) for
15 minutes.
3 Release pressure until reaching the atmosphere level, as
low as 0.03 MPaG (5 PSIG).
Step 2
1 Vacuum until the pressure
manufacturer
Yokogawa & CO.,Ltd
reaches 1000 microns
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