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7.2 Maximum Length of Lines
The maximum length of interconnecting line is 150 feet. Always use the shortest
length possible with a minimum number of bends. Additional compressor oil is not
required for any length up to 150 feet.
NOTE: Excessively long refrigerant lines cause loss of equipment capacity.
7.3 Outdoor Unit Installed Above or Below Indoor Coil
Use the following guidelines when installing the unit:
1.
Expansion Valve Coil:
a. The vertical separation cannot exceed the value in Tables 4 and 5.
b. No changes are required for expansion valve coils.
2.
It is recommended to use the smallest liquid line size permitted to minimize the
system charge.
3.
Tables 4 and 5 may be used for sizing horizontal runs.
7.4 Tubing Installation
Observe the following when installing correctly sized type "L" refrigerant tubing
between the condensing unit and evaporator coil:
•
If a portion of the liquid line passes through a hot area where liquid refrigerant
can be heated to form vapor, insulating the liquid line is required.
•
Use clean, dehydrated, sealed refrigeration grade tubing.
•
Always keep tubing sealed until tubing is in place and connections are to be
made.
•
Blow out the liquid and vapor lines with dry nitrogen before connecting to the
outdoor unit and indoor coil. Any debris in the line set will end up plugging the
expansion device.
•
As an added precaution, a high quality filter drier is standard on R-410A units.
•
Do not allow the vapor line and liquid line to be in contact with each other. This
causes an undesirable heat transfer resulting in capacity loss and increased
power consumption. The vapor line must be insulated.
•
If tubing has been cut, make sure ends are deburred while holding in a position
to prevent chips from falling into tubing. Burrs such as those caused by tubing
cutters can affect performance dramatically, particularly on small liquid line
sizes.
•
For best operation, keep tubing run as short as possible with a minimum num-
ber of elbows or bends.
•
Locations where the tubing will be exposed to mechanical damage should be
avoided. If it is necessary to use such locations, the copper tubing should be
housed to prevent damage.
•
If tubing is to be run underground, it must be run in a sealed watertight chase.
•
Use care in routing tubing and do not kink or twist. Use a good tubing bender
on the vapor line to prevent kinking.
•
Route the tubing using temporary hangers, then straighten the tubing and
install permanent hangers. Line must be adequately supported.
•
The vapor line must be insulated to prevent dripping (sweating) and prevent
performance losses. Armaflex and Rubatex are satisfactory insulations for this
purpose. Use 1/2" minimum insulation thickness, additional insulation may be
required for long runs.
•
Check Table 4 for the correct vapor line size. Check Table 5 for the correct liq-
uid line size.
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