Haier MVHP036MV2AA Installation Manual page 13

Installation instruction
• Weld the pipe while charging with nitrogen or it will cause impurities (including
a film of oxidation) to clog the capillary and the expansion valve which may lead
to deadly accidents.
• Protect the pipe ends from getting water and other impurities into
the pipes (from welding, filed or being sealed with adhesive tape).
Flat
Brazing
• The refrigerant pipe should be clean. The nitrogen should flow at
pressure around 29PSI(0.2Mpa) and when charging the nitrogen,
stop up the end of the pipe by hand to increase the pressure in the
pipe, then move your hand and stop up the other end.
• Close the valves fully when connecting the pipes.
• When welding the valve and pipes, use a wet cloth to cool down the valve and
pipes.
(6) Leakage test
1. The outdoor unit has been tested for leakages from the factory. After connecting the distributing pipe, test for leakages
from the outdoor check valve and the indoor pipe. While testing, the valves should be close.
2. Refer to the below figure to charge nitrogen into the unit to test. Never use chlorine, oxygen, flammable gas for the
leakage test. Apply pressure on both the gas pipe and the liquid pipe.
3. Apply the pressure step by step to the target pressure.
a. Pressurize to 72.5PSI(0.5MPa) for more than 5 minutes, check if pressure goes down.
b. Pressurize to 217.5PSI(1.5MPa) for more than 5 minutes, check if pressure goes down.
c. Pressurize to the target pressure 580PSI(4.0MPa), record the temp. and the pressure.
d. Leave it at 4.0MPa for 1 day or more, if the pressure does not go down, the test is complete.
Note that when the temp. changes
by 1degree, pressure will change
1.45PSI(0.01MPa). Correct
the pressure as needed.
e. After performing a~d, if the pressure
goes down, there is leakage. Check
any brazed and flared connections
using soapy water. Fix the leakage and
perform test again.
4. After the leakage test evacuate the
system.
(7) Evacuation
Evacute at the liquid service valve and both sides of the gas service valve.
Operation procedure:
Adhesive tape
Nitrogen
after reaching -14.645PSI
(101KPa) or less (below
-755mmHg), let the vacuum
pump run continuously for 1
hour or more.
if vacuum needle rises, it shows there is water or leakage in the
system, please correct the problem and then evacuate again.
11
Seal the pipe end with
adhesive tape or the stopper
to increase the resistance, fill
up the pipe with nitrogen.
Taping
Only nitrogen gas
can be used
1st side
Source valve
To indoor
Gauge manifold
Lo Hi
Lo handle Hi handle
leave it for over 1
hour, vacuum
gauge does not arise.
<N2>
Brazing
2nd side
29PSI
(0.2MPa)
Hand
Check valve
Gas pipe
Gas pipe
Check hole
Outdoor