Lennox iComfort Elite XCZ20 Installation Instructions Manual page 4

IMPORTANT !
If this unit is being matched with an approved line set or
indoor unit coil that was previously charged with mineral
oil, or if it is being matched with a coil which was manu­
factured before January of 1999, the coil and line set
must be flushed prior to installation. Take care to empty
all existing traps. Polyol ester (POE) oils are used in Len­
nox units charged with HFC-410A refrigerant. Residual
mineral oil can act as an insulator, preventing proper
heat transfer. It can also clog the expansion device and
reduce system performance and capacity.
Failure to properly flush the system per the XCZ20 Instal­
lation and Service Procedures will void the warranty.
WARNING
When using a high-pressure gas such as
nitrogen to pressurize a refrigeration or
air conditioning system, use a regulator
that can control the pressure down to 1 or
2 psig (6.9 to 13.8 kPa).
WARNING
Fire, Explosion and Personal Safety Haz­
ard. Failure to follow this warning could
result in damage, personal injury or
death.
Never use oxygen to pressurize or purge
refrigeration lines. Oxygen, when ex­
posed to a spark or open flame, can cause
fire and/or an explosion, that could result
in property damage, personal injury or
death.
IMPORTANT !
Some scroll compressors have an internal vacuum
protector that will unload scrolls when suction pres­
sure goes below 20 psig. A hissing sound will be heard
when the compressor is running unloaded. Protector
will reset when low pressure in system is raised above
40 psig. DO NOT REPLACE COMPRESSOR.
Table 1. Standard Refrigerant Line Set — Up to 50 Linear Feet in Length
Model Number (-xx*)
Model Number (-xx*)
XCZ20-024-230-XX
XCZ20-036-230-XX
XCZ20-048-230-XX
XCZ20-060-230-XX
* Applicable to all minor revision numbers unless otherwise specified.
** Some applications may require a field-provided 1-1/8" to 7/8" adapter.
Valve Size Connections
Liquid Line Suction Line
3/8" (10 mm) 3/4" (19 mm)
3/8" (10 mm) 7/8" (22 mm)
3/8" (10 mm) 1-1/8" (29 mm) **
If unit is equipped with a crankcase heater, and outdoor
ambient temperature is below 60°F, unit should be ener­
gized 24 hours before start­up to prevent compressor
damage as a result of slugging.
The XCZ20 is a variable capacity cooling system utilizing
variable speed compressor technology. With the variable
speed compressor and variable pumping capacity, addi­
tional consideration must be given to refrigerant piping siz­
ing and application. The guidelines below are to be used
exclusively for the XCZ20 systems.
COOLING SYSTEM (HFC­410A)
S
Total equivalent length equals 180 feet (piping and all
fittings included).
NOTE — Length is general guide. Lengths may be more or
less, depending on remaining system design factors.
S
Maximum linear (actual) length = 150 feet.
S
Maximum linear liquid lift = 60 feet.
NOTE — Maximum lifts are dependent on total length,
number of elbows, etc. that contribute to total pressure
drop.
S
Maximum length vapor riser equals 60 feet.
S
Up to 50 Linear Feet: Use rated line sizes listed in
table 1.
S
Between 51 and 150 Linear Feet: Crankcase heater
and non­bleed port TXV factory installed. No addition­
al components required. Vertical vapor riser must be
sized to the vapor riser listed in the table 2 on systems
with line sets longer than 51 feet. Use tables 2 and 3
to determine the correct liquid and vapor line sizes.
S
Over 150 Linear Feet: not recommended.
S
Additional oil is not required for systems with line
lengths up to 150 feet.
SUCTION TRAPS
For systems with the outdoor unit 5 ­ 60 feet above the in­
door unit, one trap must be installed at the bottom of the
suction riser.
Inches (mm)
L15 Line Set Model
L15-41-30
L15-65-40
L15-65-50
Field-fabricated
Page 4
IMPORTANT !
Recommended Line Sets
Line Set Length
30 feet (9.1 m)
40 feet (12.2 m)
50 feet (15.2 m)
Catalog Number
89J60
89J61
89J62