Leak Test And Vacuum Drying - Daikin ERLQ036BAVJU Manuel D'installation

Cautions for necessity of a trap
Since there is fear of the oil held inside the riser piping flowing back into
the compressor when stopped and causing liquid compression
phenomenon, or cases of deterioration of oil return, it will be necessary
to provide a trap at an appropriate place in the riser gas piping.
Trap installation spacing. (See figure 4)
A Outdoor unit
B Indoor unit
C Gas piping
D Liquid piping
E Oiltrap
H Install trap at each difference in height of 33 ft (10 m).
A trap is not necessary when the outdoor unit is installed in a
higher position than the indoor unit.
L
EAK TEST AND VACUUM DRYING
When all piping work is complete and the outdoor unit is connected to
the indoor unit, it is necessary to (a) check for any leakages in the
refrigerant piping and (b) to perform vacuum drying to remove all
moisture in the refrigerant piping.
If there is a possibility of moisture being present in the refrigerant
piping (for example, rainwater may have entered the piping), first
carry out the vacuum drying procedure below until all moisture has
been removed.
General guidelines
All piping inside the unit has been factory tested for leaks.
Use a 2-stage vacuum pump with a non-return valve which can
evacuate to a gauge pressure of –14.6 psi [–100.7 kPa (5 Torr
absolute, –755 mm Hg)].
Connect the vacuum pump to both the service port of the gas
stop valve and the liquid stop valve to increase efficiency.
Do not purge the air with refrigerants. Use a
NOTE
vacuum pump to evacuate the installation. No
additional refrigerant is provided for air purging.
Make sure that the gas stop valve and liquid stop
valve are firmly closed before performing the leak
test or vacuum drying.
Setup
(See figure 5)
1 Pressure gauge
2 Nitrogen
3 Refrigerant
4 Weighing machine
5 Vacuum pump
6 Stop valve
ERLQ036~054BAVJU
Outdoor unit for air to water heat pump
4PW55905-1
Leak test
The leak test must satisfy specification EN 378-2.
1 Vacuum leak test
1.1 Evacuate the system from the liquid and gas piping to
–14.6 psi [–100.7 kPa (5 Torr absolute)].
1.2 Once reached, turn off the vacuum pump and check that
the pressure does not rise for at least 1 minute.
1.3 Should the pressure rise, the system may either contain
moisture (see vacuum drying below) or have leaks.
2 Pressure leak test
2.1 Break the vacuum by pressurizing with nitrogen gas to a
minimum gauge pressure of 29 psi [0.2 MPa (2 bar)].
Never set the gauge pressure higher than the maximum
operation pressure of the unit, i.e. 580 psi [4.0 MPa
(40 bar)].
2.2 Test for leaks by applying a bubble test solution to all piping
connections.
Make sure to use a recommended bubble test
solution from your wholesaler.
Do not use soap water, which may cause
cracking of flare nuts (soap water may contain
salt, which absorbs moisture that will freeze
when the piping gets cold), and/or lead to
corrosion of flared joints (soap water may contain
ammonia which causes a corrosive effect
between the brass flare nut and the copper flare).
2.3 Discharge all nitrogen gas.
Vacuum drying
To remove all moisture from the system, proceed as follows:
1. Evacuate the system for at least 2 hours to a target vacuum of
–14.6 psi [–100.7 kPa (5 Torr absolute)].
2. Check that, with the vacuum pump turned off, the target vacuum
is maintained for at least 1 hour.
3. Should you fail to reach the target vacuum within 2 hours or
maintain the vacuum for 1 hour, the system may contain too
much moisture.
4. In that case, break the vacuum by pressurizing with nitrogen gas
to a gauge pressure of 7.3 psi [0.05 MPa (0.5 bar)] and repeat
steps 1 to 3 until all moisture has been removed.
5. The stop valves can now be opened, and/or additional
refrigerant can be charged (see "Charging refrigerant" on
page 10).
After opening the stop valve, it is possible that the pressure
in the refrigerant piping does not rise. This might be
caused by e.g. the closed state of the expansion valve in
the outdoor unit circuit, but does not present any problem
for correct operation of the unit.
Installation manual
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