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 are 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 (eld-supplied) after the insulation work is completed.
NOTE
If the gap is not covered, the unit may be damaged if snow, rain
water or animals enter the unit.
For piping from botton base
For piping from front or
rear side piping cover
Piping cover
(attached to unit)
Gas pipe
Liquid pipe
Cover the gap
with insulations
Gas pipe
Liquid pipe
Piping
cover
Cover the gap with a
packing (eld-supplied)
9.2 VACUUMING
1 Connect a manifold gauge and vacuum pump to the check
joints*.
Heat pump system
High/low pressure gas stop valve
Liquid stop valve
Heat recovery system
High/low pressure gas stop valve
Low pressure gas stop valve
Liquid stop valve
2 Continue vacuum pumping work until the pressure reaches
-0.1MPa (-756mmHg) or lower for one to two hours. After
vacuum pumping work, stop the vacuum pumping and leave
the gauge for one hour. Check to ensure that the pressure in
the manifold gauge does not increase.
3 Tighten the caps of check joint according to the specied
torque (Item 8.1-(2)-(e)) after the vacuum pumping work.
4 If the pressure inside the gauge does not reach -0.1MPa
(-756mmHg), it is considered that there is a gas leakage.
Check for any gas leakage once again. If no leakage exists,
operate the vacuum pumping for one to two hours. If moisture
remains inside the pipes, the compressor may be damaged.
NOTE
• If tools or measuring instruments come into contact with the
refrigerant, use the tools or the measuring instruments exclu-
sively for R410A.
• DO NOT perform vacuuming pumping work with valves of the
outdoor units open. Otherwise, the refrigerant charged before
shipment may leak and it may result in failure.
50
PMML0294A rev.2 - 07/2014
Additional refrigerant charge
PMML0294A_rev.2_02-2014.indb 50 14/07/2014 12:28:30
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