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• Lines must be clean refrigeration-grade copper.
• Avoid removing caps and plugs from the heat pump or lines
until they are ready to be connected.
• Insulate the vapor line with refrigerant line insulation ¼"
wall thickness or greater.
Proper system performance and oil management depend
on properly selecting the liquid and vapor line sizes. Refer to
Table 3 below for the proper size of field supplied lines. The
maximum allowable refrigerant line length is 100 ft.
Model
up to
25 to
24 ft.
39 ft.
3/4 in.
-024K units
(19 mm)
7/8 in.
-036K units
(22 mm)
7/8 in.
-048K units
(22 mm)
7/8 in.
-060K units
(22 mm)
Table 3. Permissible refrigerant line Sizes
The maximum vertical elevation between the heat pump and
indoor coil is 50 ft. Systems that require more elevation will
need to have an oil trap installed in the vapor line. Refer to
Nordyne Application Guideline for Refrigerant Lines Over 75
Feet (document 044B-0600) for piping details.
A filter drier is supplied with the heat pump. It is required and
recommended that it be installed near the indoor coil.
It is recommended to replace existing refrigerant lines that
were previously used for an R-22 system. If the lines are not
replaced, they must be properly flushed by a licensed EPA
certified technician in accordance with the manufacturer's
instructions and established procedures.
Brazing
Use the appropriate safety equipment while brazing. Items
such as gloves, safety glasses, proper ventilation, and a fire
extinguisher should be used.
1. Route the refrigerant lines from the indoor coil to the service
valves on the heat pump. Avoid sharp radius bends and
turns. See Figure 5 (page 10)
2. Make sure that the vapor line is properly insulated for the
entire length of the run for maximum system efficiency.
Improper insulation may also create condensation and result
in water damage to the equipment and building structure.
3. Remove the valve cores from the heat pump service valves.
Wrap the valves completely with wet rags to protect them
from overheating during the brazing operation.
4. Connect both the vapor and liquid lines. Tubes should be
round, de-burred and free of debris. Use a phosphorous
and copper or silver brazing alloy for the joints. Do not use
soft solder with a low melting point.
5. Connect the indoor lines according to the indoor unit
instructions. The indoor coil will require the same alloys and
wet rags to protect the sensors from excessive heat on the
refrigerant lines.
line Set lengths
liquid
Vapor Line
40 to
75 to
75 ft.
100 ft.
100 ft.
7/8 in.
1 1/8 in.
(22 mm)
(29 mm)
(10 mm)
1 1/8 in.
(29 mm)
(10 mm)
1 1/8 in.
(29 mm)
(10 mm)
1 1/8 in.
(29 mm)
(10 mm)
6. Allow the service valves to cool and replace the valve cores.
7. Leak test the connections using low pressure dry nitrogen.
System Evacuation
1. Connect the refrigerant gauge manifold to both the vapor
and liquid service valves. See Figure 5. Connect the center
port to the vacuum pump.
2. Open both manifold valves and start the vacuum pump.
After a short time, it is recommended to close the manifold
valves and stop the vacuum pump to look for a rapid loss
of vacuum. Loss of vacuum indicates that there is a leak in
the system. Repeat the leak test if required.
3. Evacuate the system to at least 500 microns to remove
line
non-condensables and water vapor. Close the manifold
up to
valves and remove the vacuum pump.
4. Connect the refrigerant tank to the center manifold port of
3/8 in.
the gauge set. Pressurize the system enough to break the
vacuum.
3/8 in.
5. Open both service valves by turning the valve stems ¼ turn
counterclockwise. The stem will be in line with the tubes.
3/8 in.
Replace the stem caps and tighten. Proceed with Refrigerant
Charging section.
3/8 in.
The heat pump system contains liquid and
gaseous refrigerant under pressure. adjustment
of refrigerant charge should only be done by a
qualified, EPa certified technician thoroughly
familiar with this type of equipment. under no
circumstances should the homeowner attempt to
install and/or service this equipment. Failure to
comply with this warning could result in equipment
damage, personal injury, or death.
refrigerant charging
• The unit must be charged at a fixed speed setting. For this
purpose the thermostat needs to be wired and powered
prior to charging.
• The heat pump is factory charged for field installed lines 15
ft. in length with the matching indoor equipment. Adjustments
to the refrigerant charge will be required for other length
and tube sizes. For lines longer than 15 ft with a 3/8" OD
liquid line, add 0.52 oz. per ft. See Table 4 (page 6).
• Small variations in the temperatures and pressures are
normal due to differences in the installation.
• Large variations in the temperatures and pressures
could indicate incorrect charge or another problem with a
component in the system.
The preferred method of charging is by weighing in the
additional refrigerant required. If a charging scale is not
available, the next preferred charging method would be to
use the sub-cooling method in cooling mode.
charging operation
For charging in the field, the unit should be run with a
call for second stage cooling (or heating, if the outdoor
ambient temperature is below 60° F), with both Y1 and Y2
WarnInG:
noTES:
5
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