Lennox SL25XPV Series Installation Instructions Manual page 5

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
Polyvinyl ether (PVE) 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
Some scroll compressors have 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.
ADDING REFRIGERANT FOR LONG LINE SETS
WEIGH IN
CHARGING METHOD FOR LONG LINE SETS
64ºF (17.7ºC) and Below
Adjust amount. for variation in
line set length and liquid line
Amount specified
diameter using table below.
on nameplate
+
Liquid Line
Set Diameter
5/16"
3/8"
1/2"
Total charge
=
HFC-410A
[(Line
(ounces per foot)
Example
0.40
Factory charge for 3/8" is 0.60 oz/ft x 15 = 9.0 ounces.
0.60
1.00
FIGURE 1. Using HFC-410A Weigh In Method
The SL25XPV is a variable-capacity cooling system uti-
lizing variable speed compressor technology. With the
variable speed compressor and variable pumping capac-
ity, additional consideration must be given to refrigerant
piping sizing and application. The guidelines below are to
be used exclusively for the SL25XPV systems.
HEAT PUMP 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 1.
• 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 the table 2 on systems with
line sets longer than 51 feet. Use tables 2 and 3 to de-
termine 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.
NOTE — Insulate liquid line when it is routed through areas where
the surrounding ambient temperature could become higher than the
temperature of the liquid line or when pressure drop is equal to or
greater than 20 psig.
NOTE — The above nameplate is for illustration purposes only. Go to
actual nameplate on outdoor unit for charge information.
Charging Formula for Liquid Line Charge Adjustments
Page 5