-SCS C
ONDENSER
IOM
M
ANUAL
14
Figure 11. Sample Nameplate
CAUTION
Improper wire connections will result in the reverse
rotation of the fan. To correct this problem, exchange any two
of the incoming main power wires at the main power circuit
breaker. Do NOT rewire the unit’s individual components.
Identify the options that were purchased with your system to
confirm which field connections are required. The number
of control conductors needed will vary depending on the
options and type of control method being used. Refer to the
electrical drawing supplied with your unit to determine the
total number of interconnecting conductors required for
your equipment and for the proper wire terminations.
2.6.1.1
Condenser Enable Feature
As an option, the installer may wire a 2-conductor control
cable between the A/C system and the condenser, so the
system controller may enable the condenser to operate only
when the compressor is running. You must remove the jumper
(X2:1-X2:2) from the remote condenser terminal board
(see the condenser wiring diagram). Wire 24 VAC control
conductors from the terminal board within the A/C unit to
the remote condenser terminal board. If control wires aren’t
installed (and the jumper remains in place), the condenser is
always enabled and will turn on and off based on the
condenser’s pressure control switch setting(s).
The condenser enable feature may be used in high ambient
temperature locations to prevent the condenser from running
unnecessarily. In some cases, outdoor temperature conditions
may raise refrigerant line pressures high enough to cause
the condenser fans to start operating even if the compressor
isn’t on.
2.6.1.2
Receiver Heater Wiring
If separate base frame mounted receiver(s) are used for
SCS condensers, it will be necessary to provide a 2-conductor
cable for the heating pad(s). Connect the wires from the
terminals inside the junction box on the receiver base (see
Figure 7) to the terminal block in the condenser electric box.
Drill an entrance hole in the condenser electric box or use an
available knock-out if furnished. See the wiring diagram for
the correct wire terminal positions.
2.7
System Charging
Refrigerant charging pressures vary depending on the type
of refrigerant used in the unit. Before charging, check the unit
nameplate to confirm the type of refrigerant to use. Tables are
provided in Section 2.8 showing the temperature/pressure
characteristics for R407C and R410A.
2.7.1
R407C/R410A Refrigerant
R407C and R410A are blended refrigerants recognized for
being safer for the environment. These refrigerants contain no
chlorine, the component in HCFC’s that destroys the earth’s
ozone layer. However, the same care should be taken to
prevent leakage because R407C and R410A can contribute
to the greenhouse effect if released. If the refrigerant gas is
released in an enclosed space, it can suffocate.
Refrigerants that are multi-component blends have
component parts with different volatilities that result in a
change in composition and saturation temperature as
evaporation and condensation occur. Typically, the
composition of R407C vapor is different than that of R407C
liquid within a contained system. The composition of liquid
R407C refrigerant remains relatively constant, however, the
refrigerant vapor tends to separate into its component parts
even when circulating.
Refrigerant R410A is similar to R407C in that it is a blended
refrigerant that consists of component parts, however, the
component parts of R410A refrigerant have the same
composition at various operating temperature/pressures in
the liquid phase and gas phase reducing the temperature
glide effect experienced with R407C. R410A operates at
