14
Refrigerant Piping Connections
WARNING
!
Refrigerant leaks are unlikely; however, if a
refriger ant leak occurs, open a door or windows
to dilute the refrigerant in the room. Turn off the
unit and all other appliances that may cause
a spark. Call a li censed professional HVAC
technician (or equiva lent) to repair the leak.
Use only R-410A refrigerant to charge this
system. Use of other refrigerant or gas will
damage the equipment.
Do not allow air or other contaminants to
enter sys tem during installation of refrigerant
piping. Con
taminants will result in lower
system capacity and abnormally high operating
pressures and may res ult in system failure or
explosion.
Insulate all refrigerant piping.
Refrigerant pipes may be very hot during unit
opera tion. Do not allow contact between wiring
and bare copper pipes.
After refrigerant piping connections have been
completed, check the system for leaks per
commis sioning instructions.
•
Both liquid and gas (vapor) lines must be indi
-
vidually insulated.
•
Field piping consists of three HVAC/R field-pro
-
vided copper refrigerant lines connected to the
outdoor unit. These lines carry the liquid and va-
por refrigerant to and from the mode selection
box(es).
• Refrigerant piping and wiring connections can be
brought into the outdoor unit through openings
provided in the front, side(s), or underside (rec
-
ommended) of the unit.
• Refrigerant piping must be connected using
mode selection boxes and individual branch pipe
kits.
Six mode selection boxes are available in
varying sizes to accommodate connection of one
to 41 indoor units.
• The following restrictions apply to each VRB sys-
tem:
•
Total refrigerant pipe length 3280 ft. (1000 m)
•
Longest pipe length actual) 574 ft. (175 m)
•
Level difference between indoor units 98 ft.
(30 m)
•
Piping length from the first branch pipe to the
farthest indoor unit 132/295 ft. (40/90 m)
•
For each branch pipe, allow 20” (508 mm) of
equivalent length.
!
Contact the Lennox VRF applications department
for assistance.
• When the outdoor unit is installed 164 feet (50
m) or more above the indoor units, install an oil
return trap every 33 feet (10 m) in the main low
pressure gas pipe. See Figure 13 for trap speci-
fications.
≥1ft
≥1ft
Figure 13. Oil Return Trap
•
To extend the length from the first branch pipe to
the farthest indoor unit beyond 132 ft. (40 m) and
up to 295 ft. (90 m), the following three conditions
must be met.
1. Increase diameter of the main pipe between
the first and the last branch pipes. If the diam
-
eter of the pipe is the same as the main outdoor
pipe, then it does not need to be increased.
Ex: If 132 ft.<L1+L7+L9+L10 ≤ 295 ft., in
-
crease the diameter of all the pipes by one
size.
2. The length from the indoor unit to the nearest
branch pipe must be 132 ft. (40 m) or less.
Ex: a,b,c,d,e,f,g,h,i,j,k,l,m ≤ 132 ft.
3.
The difference between [the distance from
the outdoor unit to the farthest indoor
unit] and [the distance from the outdoor
unit to the nearest indoor unit] is ≤132 ft.
E x : ( L 1 + L 7 + L 9 + L 1 1 + 1 1 + j + k + n )
- ( L 1 + L 7 + L 8 + p )
≤ 132 ft.
!
Contact the Lennox VRF applications department
for assistance.
IMPORTANT!
The compressor in this unit contains PVE oil
(Polyvinylether). PVE oil is formulated for hy-
drofluorocarbon (HFC) refrigerants, such as R-
410a, which this system contains. While it may
have some miscibility properties with mineral
based oil and POE oil (Polyolester), you should
not mix PVE oil with any other type of refriger-
ant oil.
•
When the outdoor unit is 132 feet (40 m) or more
below the indoor units, increase the diameter of
the liquid line pipe from the outdoor unit to the
first branch pipe by one size.
!
Contact the Len-
nox VRF applications department for assistance.
Summary of Contents for VPB Series
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