York YD480 Series Installation Manual page 11

cooled. The flow of nitrogen will prevent oxidation of the
copper lines during installation.
Always punch a small hole in sealing disks before unbrazing to
prevent the pressure in the line from blowing them off. Do not
use a drill as copper shavings can enter system.
NOTE: Solenoid and hot gas bypass valves (if used) should be
opened manually or electrically during brazing or
evacuating.
NOTE: Schrader valves located on unit service valves should
have their stem removed during brazing to prevent
damage to the valve.
Start Installation
Start Installation of main lines at the condenser unit. Verify the
service valves are fully seated by screwing the stem of both
valves down into the valve body until it stops. Remove the
Schrader valve stem and connect a low-pressure nitrogen
source to the service port on the suction line valve body. Punch
a small hole in the sealing disk; the flow of nitrogen will prevent
any debris from entering the system. Wrap the valve body with
a wet rag to prevent overheating during the brazing process.
Overheating the valve will damage the valve seals. Unbraze the
sealing disk, cool the valve body and prepare the joint for
connections of the main lines. Repeat for the liquid line valve
body.
Never remove a cap from an access port unless the
valve is fully back-seated with its valve stem in the
maximum counter-clockwise position because the
refrigerant charge will be lost. Always use a refrigeration
valve wrench to open and close these service valves.
Connect the main liquid line to the liquid line service valve on
the condenser section, while maintaining a flow of nitrogen.
Cool the valve body and replace the Schrader valve stem on
the service port of the liquid line service valve.
Install the liquid line from the condenser unit to the evaporator
liquid connection, maintaining a flow of nitrogen during all
brazing operations.
The filter-drier and sight glass must be located in this line,
leaving the O.D. unit.
Connect a low-pressure nitrogen source to the Schrader valve
located on the evaporator unit coil headers. Punch a small hole
in the sealing disks, the flow of nitrogen will prevent any debris
from entering the system. Unbraze both liquid and suction
Johnson Controls Unitary Products
sealing disks and prepare the joints for connections of the main
lines.
Connect the main liquid line to the liquid line connection on the
evaporator unit, while maintaining a flow of nitrogen.
Make the suction line connection at the evaporator and run the
line to the condenser unit. Connect the main suction line to the
suction line service line on the condenser unit, while
maintaining a flow of nitrogen. Cool the valve body and replace
the Schrader valve stem on the service port of the suction line
service valve.
Once the brazing process is complete, leak testing should be
performed on all interconnecting piping and the evaporator
before proper evacuation to 500 microns is performed. Once
the line set and evaporator unit is properly evacuated the
service valves can be opened and the condenser unit is now
ready to charge with the appropriate weight of refrigerant.
Calculate the correct system charge for the condenser unit, the
evaporator unit and the field line set. Charge the system by
introducing liquid refrigerant into the liquid line through the
liquid port connection. Complete adding the refrigerant in vapor
form into the suction port when the compressor is started.
The correct refrigerant pressures are indicated as shown in
Figures 14 through 15.
This system uses R-410A Refrigerant which operates at
higher pressures than R-22. No other refrigerant may be
used in this system. Gage sets, hoses, refrigerant
containers and recovery systems must be designed to
handle R-410A. If you are unsure, consult the
equipment manufacturer. Failure to use R-410A
compatible servicing equipment may result in property
damage or injury.
Wear safety glasses and gloves when handling
refrigerants. Failure to follow this warning can cause
serious personal injury.
NOTE: This instruction covers the installation and operation of
the basic condenser unit. For refrigerant piping
installation instructions refer to document 247077
"Application Data - General Piping Recommendations
for Split System Air Conditioning and Heat Pumps".
5012886-YIM-B-0517
11