Johnson Controls SA PD 180 THRU 240 - Manual (Page 11)

430645-YIM-D-0610
Johnson Controls Unitary Products 11
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 stems removed during brazing to prevent
damage to the valve and reduce system evacuation
time.
Start Installation
Start the installation of main lines at the heat pump. Verify
holding charge in unit by cracking open valve. If pressure is
present, close valve and proceed with installation. If no
pressure is present, check system for leaks.
Verify all service valves are fully seated by screwing the stems
of both valves down into the valve bodies until they stop.
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.
Connect the main liquid line to the liquid line service valve
connection, while maintaining a flow of nitrogen. Cool the valve
body and replace the Schrader valve stem in the service port.
Install the liquid line from the heat pump to the evaporator liquid
connection, maintaining a flow of nitrogen during all brazing
operations.
The filter-drier and sight glass must be located in the liquid line,
leaving the O.D. unit.
Connect a low-pressure nitrogen source to the Schrader valve
located on the evaporator section 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 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 section, while maintaining a flow of nitrogen.
Make the suction line connection at the evaporator and run the
line to the heat pump. Connect the main suction line to the
suction line service valve connection, while maintaining a flow
of nitrogen. Cool the valve body and replace the Schrader valve
stem in the service port.
Once the brazing process is complete, leak testing should be
done on all interconnecting piping and the evaporator before
proper evacuation to below 500 microns is performed.
Verify evacuation with micron guage or thermocouple. Once the
line set and evaporator section is properly evacuated, the
service valves can be opened and the heat pump is now ready
to charge with the appropriate weight of refrigerant. Calculate
the correct system charge for the outdoor unit, the indoor 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 11 thru 16.
NOTE: This instruction covers the installation and operation of
the basic heat pump. For refrigerant piping installation
instructions refer to document 247077 "Application
Data - General Piping Recommendations for Split
System Air Conditioning and Heat Pumps".
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.
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.