York R410A User Manual page 21

Installation Procedure
(4) Air discharging method
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).
Indoor
Completely tightened
Completely tightened
Indoor units
First step: 43.5PSI(3.0kg/cm
Second step: 217.5PSI (15kg/cm
Large leakage will be found.
Third step: 435PSI (30kg/cm
Little leakage will be found.
Check if the pressure drops
The pressure does not drop-passed
The pressure drops-check the leaking point.
From pressurizing to 24 hours later, each 1
ambient temperature will make 1.45PSI (0.1kg/cm
change. It shall be corrected during test.
Checking the leaking point
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.
(5) Piping and indoor unit vacuumizing
Use vacuum pump to perform vacuumizing. It is strictly forbidden to use the refrigerant to remove the air inside the
system.
After air tightness test and discharging all the nitrogen,
connect the vacuum pump as
the following figure shown.
Indoor units
Outdoor
Flare part
Flare part
3-way valve totally closed
(Liquid side)
2
g) pressurize over 3 minutes.
2
g) pressurize over 3 minutes.
2
g) pressurize about 24 hours.
difference of
2
g) pressure
Indoor Outdoor
Completely tightened
Completely tightened
Low pressure peizometer
3-way valve totally closed
(Gas side)
VL VH
Discharging valve
Dropping valve
Manhole
Outdoor units
Line pressure gauge
Tubing bring brazed
Sweat joint
Large slip-on
connector
Service house
Low pressure peizometer
3-way valve totally closed
(Gas side)
Flare part
Discharging valve
Flare part
Outdoor units
3-way valve totally closed
(Liquid side)
21
Outdoor Unit
High pressure peizometer
Meter separator
Nitrogen tank
Cylinder pressure gauge
Cylinder of nitrogen
High pressure peizometer
Meter separator
VL VH
P
Vacuum pump