IMPORTANT:
Check factory wiring and wire connections to
ensure terminations are secured properly. Check wire routing to
ensure wires are not in contact with tubing, sheet metal, etc.
VIII.
INSTALL ELECTRICAL ACCESSORIES
A.
General
Refer to the individual instructions packaged with kits or acces-
sories when installing.
CAUTION:
Low-ambient kits are not available for
2-speed units. Do not attempt to operate below 55°F or
modify control system for low-ambient operation. Com-
pressor damage may occur.
Available electrical accessories include latent capacity control. See
Table 2 and Fig. 7 for typical accessory wiring diagrams.
B.
Latent Capacity Control (LCC)
The purpose of an LCC is to provide a dehumidification mode to
assure a 75 percent or less system sensible heat ratio. If indoor unit
installed contains an ICM blower (such as an FK4C fan coil or a
333(B,J)AV or 355MAV gas furnace), no LCC is required. Indoor
products with ICM blowers have enough CFM range to provide
proper airflow for low-speed cooling. If indoor unit installed has a
standard PSC blower motor, the low-speed airflow available is too
great to assure 75 percent or less system sensible heat ratio. The
LCC for standard blower products consists of a standard humidis-
tat which opens contacts on humidity rise and a pilot duty relay
with 24-v coil.
NOTE:
If an LCC is desired, low-speed airflow must be main-
tained so that a minimum of 300 CFM/ton can be supplied during
high-speed LCC operation.
LCC OPERATION FOR TYPICAL PSC FAN COILS
The standard blower operation for systems with typical PSC fan
coils is covered in Fig. 7A, B, and D. The blower runs in high
speed regardless if compressor operation is high or low speed.
When the LCC is wired according to Fig. 7A, B, or D and humidity
rises, the humidistat contacts open and de-energize the relay. If
relay is de-energized, the system operates on high-speed compres-
sor and high-speed airflow until humidistat closes. Fig. 7C shows
the wiring with a Bryant Thermidistat which controls temperature
and humidity level without the need for an additional humidistat
and relay.
LCC OPERATION FOR TYPICAL PSC FURNACES
The standard blower operation of systems with typical PSC
furnaces is covered in Fig. 7J, K, M, N, P, or R. The blower runs
in high or low speed in conjunction with compressor high- or
low-speed operation. When the LCC is wired according to Fig. 7K,
M, N, P, or R and humidity rises, the humidistat contacts open and
de-energize the relay. If relay is de-energized, the system operates
on high-speed compressor and low-speed airflow until humidistat
closes. Fig. 7L and 7Q shows the wiring with a Bryant Thermi-
distat which controls temperature and humidity level without the
need for an additional humidistat and relay.
Fig. 6—Line Power Connections
A91306
CONTACTOR
DISCONNECT
PER N. E. C. AND/ OR
LOCAL CODES
FIELD POWER
WIRING
FIELD GROUND
WIRING
GROUND
LUG
TABLE 2—WIRING DIAGRAM REFERENCE
INDOOR PRODUCT
THERMOSTAT
CONTROLS
DIAGRAM LETTER
IN FIG. 7
Standard Fan Coil
Bryant Programmable (Model 2S)
Latent Capacity
A
Bryant Non-Programmable (Model 2S)
Latent Capacity
B
Bryant Thermidistat™ Control
Humidifier and Outdoor Sensor
C
Other Brand Models
Latent Capacity
D
FK4C Fan Coil
Bryant Programmable (Model 2S)
—
E
Bryant Non-Programmable (Model 2S)
—
F
Bryant Thermidistat™ Control
Humidifier and Outdoor Sensor
G
Other Brand Models
—
H
Single-Stage Furnace
Bryant Programmable (Model 2S)
Latent Capacity
J
Bryant Non-Programmable (Model 2S)
Latent Capacity
K
Bryant Thermidistat™ Control
Humidifier and Outdoor Sensor
L
Other Brand Models
Latent Capacity
M
Two-Stage Furnace with PSC Blower Motor
Bryant Programmable (Model 2S)
Latent Capacity
N
Bryant Non-Programmable (Model 2S)
Latent Capacity
P
Bryant Thermidistat™ Control
Humidifier and Outdoor Sensor
Q
Other Brand Models
Latent Capacity
R
Two-Stage Furnace with ICM Blower Motor
Bryant Programmable (Model 2S)
—
S
Bryant Non-Programmable (Model 2S)
—
T
Other Brand Models
—
U
Variable-Speed 80% Non-Condensing Furnace
Bryant Thermidistat™ Control
Humidifier and Outdoor Sensor
V
Variable-Speed Condensing Furnace
Bryant Thermidistat™ Control
Humidifier and Outdoor Sensor
W
—4—
