Figure 4: Underground installation
Precautions during brazing of lines
All outdoor unit and indoor coil connections are copper-
to-copper and must be brazed with a phosphorous-
copper alloy material such as Silfos-5 or equivalent. Do
not use soft solder. The outdoor units have reusable
service valves on both the liquid and vapor connections.
The total system refrigerant charge is retained within
the outdoor unit during shipping and installation. The
reusable service valves are provided to evacuate and
charge per this instruction.
Serious service problems can be avoided by taking
adequate precautions to assure an internally clean and
dry system.
CAUTION
Dry nitrogen must always be supplied through
the tubing while it is being brazed, because the
temperature required is high enough to cause
oxidation of the copper unless an inert atmosphere
is provided. The flow of dry nitrogen should continue
until the joint has cooled. Always use a pressure
regulator and safety valve to insure that only low
pressure dry nitrogen is introduced into the tubing.
Only a small flow is necessary to displace air and
prevent oxidation.
Precautions during brazing of service
valve
Wrap a wet rag around the service valve to prevent heat
damage. See Figure 5. Also, protect all painted surfaces,
insulation, and the plastic base during brazing. After
brazing, cool the joint with a wet rag.
WARNING
This is not a backseating valve. The service access
port has a valve core. Opening or closing valve does
not close service access port. If the valve stem is
backed out past the chamfered retaining wall, the
O-ring can be damaged causing leakage or system
pressure could force the valve stem out of the valve
body possibly causing personal injury.
Open the valve by removing the service valve cap and
fully inserting a hex wrench into the stem and backing
out counterclockwise until the valve stem just touches the
chamfered retaining wall.
Connecting the refrigerant lines
1. Remove the cap and Schrader core from both the
liquid and vapor service valve service ports at the
outdoor unit. Connect low pressure nitrogen to the
liquid line service port.
2. Braze the liquid line to the liquid valve at the
outdoor unit. Be sure to wrap the valve body with a
wet rag. Allow the nitrogen to continue flowing.
3. Carefully remove the plugs from the indoor liquid
and vapor connections at the indoor coil.
4. Braze the liquid line to the indoor coil liquid
connection. Nitrogen should be flowing through
the indoor coil.
5. Slide the grommet away from the vapor connection
at the indoor coil. Braze the vapor line to the
indoor coil vapor connection. After the connection
has cooled, slide the grommet back into original
position.
6. Protect the vapor valve with a wet rag and braze
the vapor line connection to the outdoor unit.
The nitrogen flow should be exiting the system
from the vapor service port connection. After this
connection has cooled, remove the nitrogen source
from the liquid fitting service port.
7. Replace the Schrader core in the liquid and vapor
valves.
8. See Indoor expansion device.
9. Leak test all refrigerant piping connections
including the service port flare caps to be sure they
are leak tight. Do not over-tighten (between 40 in-
lb and 60 in-lb maximum).
10. Evacuate the vapor line, indoor coil, and liquid line
to 500 microns or less. See Evacuation.
Installation Manual: R-410A Outdoor Split-System Heat Pump - YH2F, THF2, RHP150 Series10
Johnson Controls Ducted Systems
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