In the first to third test steps, if the pressure drops, check the leakage in each joint
use sense of hearing, feeling and soap water, etc. methods to find the leaking point.
After confirming the leaking point, welding it again or tighten the nut tightly again.
Checking the leaking point
First step: 0.3MPa (3.
0kg/cm
2
g) pressurize
over 3 minutes.
Second step: 1.5Mpa
(15kg/cm
2
g) pressurize
over 3 minutes. Large
leakage will be found.
Third step: 3.0 MPa
(30kg/cm
2
g) pressurize
about 24 hours. Little
leakage will be found.
After finishing connection of refrigerant pipe, it shall perform air tightness test.
The air tightness test adopts nitrogen tank to give pressure according to the pipe connection
mode as the following figure shown.
The gas and liquid valve are all in close state. In order to prevent the nitrogen entering the
circulation system of outdoor unit, tighten the valve rod before giving pressure (both gas
and liquid valve rods).
Outdoor
Completely tightened
Completely tightened
Flare part
Outdoor units
Manhole
Discharging valve
3-way valve totally closed
(Gas side)
Low pressure peizometer
High pressure peizometer
Meter separator
Dropping valve
3-way valve totally closed
(Liquid side)
Nitrogen tank
VL VH
Indoor units
Indoor
Flare part
9
From pressurizing to 24 hours later, each
1*
difference of ambient temperature
will make 0.01MPa(0.1kg/cm
2
g) pressure change. It shall be corrected during test.
Check if the pressure drops
The pressure does not drop-passed
The pressure drops-check the leaking point.
5. Air discharging method
CYLINDER
OF
NITROGEN
SERVICE
HOUSE
LARGE
SLIP-ON
CONNECTOR
SWEAT
JOINT
TUBING
BRING
BRAZED
LINE
PRESSURE
GAUGE
CYLINDER
PRESSURE
GAUGE
Installation Procedure
Refrigerant piping
