508296-G01 / 31-5000753
Page 5 of 24
Issue 2231
The Clean Air Act of 1990 bans the intentional venting
of refrigerant (CFCs, HCFCs and HFCs) as of July
1, 1992. Approved methods of recovery, recycling or
reclaiming must be followed. Fines and/or incarceration
may be levied for noncompliance.
IMPORTANT
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
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
Fire, Explosion and Personal Safety
hazard. Failure to follow this warning
could result in damage, personal injury or
death.
Never use oxygen to pressurize or
purge refrigeration lines. Oxygen, when
exposed to a spark or open flame, can
cause fire and/or an explosion, that could
result in property damage, personal injury
or death.
WARNING
Some 5-ton units use scroll compressors equipped with
an internal vacuum protector that will unload scrolls
when suction pressure 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
The NS23AMA is a variable-capacity cooling system
utilizing variable speed compressor technology. With the
variable speed compressor and variable pumping capacity,
additional consideration must be given to refrigerant piping
sizing and application. The guidelines below are to be used
exclusively for the NS23AMA systems.
Cooling System (HFC410A)
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.
• Maximum linear (actual) length = 150 feet.
• Maximum linear liquid lift = 60 feet.
NOTE:
Maximum lifts are dependent on total length,
number of elbows, etc. that contribute to total pressure
drop.
• Maximum length vapor riser = 60 feet.
• Up to 50 Linear Feet:
Use rated line sizes listed in
Table 2.
• Between 51 and 150 Linear Feet:
Crankcase heater
and nonbleed port TXV factory installed. No additional
components required. Vertical vapor riser must be
sized to the vapor riser listed in Table 4 on systems
with line sets between 51 and 150 feet. Use Table 4
and Table 5 to determine the correct liquid and vapor
line sizes.
• Over 150 Linear Feet
: not recommended.
• 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
indoor unit, one trap must be installed at the bottom of the
suction riser.
