Lennox CBX32MV Installation Instructions Manual page 19

SENSOR CONNECTIONS AND WIRING
REQUIREMENTS
The following are sensor connections and wiring
requirements for the discharge air and outdoor air sensors.
Discharge Sensor (DAT)
The Air Handler Control has two screw terminals marked
Discharge Air Sensor. The sensor is REQUIRED for
EVENHEAT operation and is field mounted and ordered
separately using Lennox Catalog # 88K38.
In the EVENHEAT mode, the discharge air sensor cycles
the electric heating elements as needed to maintain the Air
Handler control EVENHEAT jumper selected discharge
setpoint.
The discharge air sensor should be mounted downstream
of the electric heat elements as illustrated in figure 15,
detail A. It must be placed in a location with unobstructed
airflow, where other accessories (such as humidifiers, UV
lights, etc.) will not interfere with its accuracy.
Wiring distance between the Control and the discharge air
sensor should not exceed 10 feet (3 meters) when wired
with 18−gauge thermostat wire.
Outdoor Air Sensor
This is a two screw terminal for connection to a Lennox
X2658 outdoor temperature sensor. The Control takes no
action on the sensor status other than to communicate the
temperature to the RSBus network. Wiring distance
between the AHC and outdoor temperature sensor should
not exceed 200 feet when wired with 18−gauge thermostat
wire.
S
Minimum temperature: −40ºF (−40ºC)
S
Maximum temperature: 70ºF (158ºC)
AIR HANDLER CONTROL 9−PIN CONNECTOR (P8)
1. Air Handler (no electric heat)
harness (wired to pins 7 and 8) which provides 230
VAC power to Air Handler Control.
2. Air Handler (with electric heat)
harness (all pin position are wired as noted in table 5).
NOTE See figure 15, detail B for wire colors.
Table 5. Electric Heat Connection (P8)
Position Function / Description
1 Heat stage 1 relay coil
2 Heat stage 2 relay coil
3 Relay coil return
4 Heat stage 3 relay coil
5 Heat stage 4 relay coil
6 Heat stage 5 relay coil
7 L1 230VAC supply from heater kit
8 L2 230 VAC supply from heater kit
9 Not Used
CONTROL CONNECTIONS AND WIRING
REQUIREMENTS
This sections provides information on communicating and
non−communicating control connections and wire run
lengths.
Two wire factory
Eight wire factory
Page 19
Table 6. Air Handler Control Connections
Communicating
Label Label Function
24VAC
R
i+ RSbus data high connection
Thermostat
i− RSbus data low connection
24VAC command (ground)
C
24VAC
R
i+ RSbus data high connection
Outdoor Unit
i− RSbus data low connection
24VAC command (ground)
C
i+
Not used.
Link
i−
Table 7. Run Length
Wire Run Length AWG #
Maximum length of wiring
for all connections on the
18
RSbus is limited to 1500
feet (457 meters).
Table 8. Air Handler Control Connections
Non−Communicating
Label Function
First−stage heating demand.
W1
Second stage heating demand. W1 input must be active to
W2
recognize second stage heat demand. .
Third stage heating demand. W1 and W2 inputs must be
W3
active to recognize third stage heat demand.
24VAC signal indicates the presence of a demand.
G
Y1 and
First and second stage cooling inputs.
Y2
24VAC common.
C
24VAC power.
R
Use in communicating system only
DH
24VAC output for humidification.
H
Use in communicating system only
L
Reversing Valve input. (Energized by thermostat in cooling
O
mode.)
Blower speed control input for Harmony Zoning or thermo-
DS
stat de−humidification control.
Blower speed control input for Harmony Zoning or thermo-
DS
stat de−humidification control.
Table 9. Run Length
Wire Run Length AWG #
Less than 100' (30m) 18
More than 100' (30m) 16
Communicating
Insulation/Core Types
Color−coded, temperature
º º
rating 95 F (35 C) minimum,
solid core. (Class II Rated
Wiring)
Non−Communicating
Insulation/Core Types
Color−coded, temperature
º º
rating 95 F (35 C) minimum,
solid core. (Class II Rated
Wiring)
CBX32MV SERIES