Справочник Пользователя для Emerson Liebert MC Microchannel Outdoor Condenser 28 - 220kW
Piping
25
Liebert
®
MC
™
5.0
P
IPING
5.1
Piping Guidelines
Indoor units and condensers both ship with holding charges of inert gas. Do not vent the condenser
until all refrigerant piping is in place, ready for connection to indoor unit and condenser.
• Use copper piping with a brazing alloy with a minimum temperature of 1350°F (732°C), such as
Sil-Fos. Avoid soft solders such as 50/50 or 95/5.
• Use a flow of dry nitrogen through the piping during brazing to prevent formation of copper oxide
scale inside the piping. When copper is heated in the presence of air, copper oxide forms. POE oil
will dissolve these oxides from inside the copper pipes and deposit them throughout the system,
clogging filter driers and affecting other system components.
• A pure dry nitrogen flow of 1-3 ft
3
/min (0.5-1.5 l/s) inside the pipe during brazing is sufficient to
displace the air. Control the flow using a suitable metering device.
• Ensure that the tubing surfaces to be brazed are clean and that the ends of the tubes have been
carefully reamed to remove any burrs.
• Ensure that all loose material has been cleaned from inside the tubing before brazing.
• Protect all refrigerant line components within 18" (460mm) of the brazing site by wrapping them
• Protect all refrigerant line components within 18" (460mm) of the brazing site by wrapping them
with wet cloth or suitable heat sink compound.
• Isolate piping from building using vibration isolating supports.
• Refer to the indoor unit’s user manual for appropriate piping sizes.
• Install traps on the hot gas (discharge) lines at the bottom of any rise over 5 feet high. If the rise
• Refer to the indoor unit’s user manual for appropriate piping sizes.
• Install traps on the hot gas (discharge) lines at the bottom of any rise over 5 feet high. If the rise
exceeds 25 feet (7.5m), then install a trap in 20 foot (6m) increments or evenly divided.
• Pitch horizontal hot gas piping down at a minimum rate of 1/2" per 10 ft. (42mm per 10m) so that
gravity will aid in moving oil in the direction of refrigerant/oil flow.
• Consult factory if Liebert Lee-Temp
™
condenser is below the evaporator or if a condenser not
equipped with Liebert Lee-Temp is more than 15 ft (4.6m) below the evaporator.
• Consult factory if piping run exceeds 150 feet (46m) equivalent length on traditional DX units.
!
WARNING
Risk of explosive discharge from high-pressure refrigerant. Can cause equipment damage,
injury or death.
Relieve pressure before working with or cutting into piping.
Relieve pressure before working with or cutting into piping.
!
WARNING
Risk of refrigerant system rupture or explosion from overpressurization. Can cause
equipment damage, injury or death.
Local building and plumbing codes may require that a fusible plug or other type of pressure
Local building and plumbing codes may require that a fusible plug or other type of pressure
relief device be installed in the system. Do not install a shutoff valve between the compressor
and the field-installed relief device.
Consult local building and plumbing codes for installation requirements of additional
Consult local building and plumbing codes for installation requirements of additional
pressure relief devices when isolation valves are installed as shown in Figure 18. Do not
isolate any refrigerant circuits from overpressurization protection.
NOTE
POE (polyol ester) oil, required with R407C/R410A and used with some R22 systems, is much
POE (polyol ester) oil, required with R407C/R410A and used with some R22 systems, is much
more hygroscopic than mineral oils. This means that POE oil absorbs water at a much faster
rate when exposed to air than previously used mineral oils. Because water is the enemy of a
reliable refrigeration system, extreme care must be used when opening systems during
installation or service. If water is absorbed into the POE oil, it will not be easily removed and
will not be removed through the normal evacuation process. If the oil is too wet, it may require
an oil change. POE oils also have a property that makes them act as a solvent in a refrigeration
system. Maintaining system cleanliness is extremely important because the oil will tend to
bring any foreign matter back to the compressor or plug the microchannel coil. Always use a
flow of dry nitrogen when brazing.