Page 4
STEP 2 – REFRIGERANT PIPING –
Flushing Existing Line Set & Indoor Coil
F
lush the existing line set per industry standards. For
more information, refer to the XP20 Installation and
Service Procedures manual available on DaveNet.
CAUTION -
DO NOT attempt to flush and re-use ex
isting line sets or indoor coil when the system con
tains
contaminants (i.e., compressor burn out).
WARNING
Refrigerant can be harmful if it is inhaled. Refrigerant
must be used and recovered responsibly.
Failure to follow this warning may result in personal
injury or death.
WARNING
Polyol ester (POE) oils used with HFC-410A refrigerant
absorb moisture very quickly. It is very important that
the refrigerant system be kept closed as much as
possible. DO NOT remove line set caps or service valve
stub caps until you are ready to make connections.
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 XP20 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.
IMPORTANT !
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 XP20 is a variable capacity heat pump 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 XP20 systems.
HEAT PUMP 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
.
