Wiring Connections; System Communication And Control Wiring - Lennox VPB036H4M Installation Instructions Manual

Wiring Connections

WARNING
Isolate the power supply before accessing unit electrical
terminals.
Install unit so that unit disconnect is accessible.
Follow all local and national codes, as well as this
installation instruction, during installation. Do NOT
overload electrical circuit, as this may lead to failure and
possible fire.
Use specified wiring and cable to make electrical
connections. Clamp cables securely and make sure that
connections are tight to avoid strain on wiring. Insecure
wiring connections may result in equipment failure and
risk of fire.
Wiring must be installed so that all cover plates can be
securely closed.
This unit must be properly grounded and protected by a
circuit breaker. The ground wire for the unit must not be
connected to a gas or water pipe, a lightning conductor
or a telephone ground wire.
Do not connect power wires to the outdoor unit until
all other wiring and piping connections have been
completed.
In the U.S.A., wiring must conform with current local
codes and the current National Electric Code (NEC). In
Canada, wiring must conform with current local codes and
the current Canadian Electrical Code (CEC).
Refer to unit nameplate for minimum circuit ampacity and
maximum overcurrent protection size.
• A dedicated Circuit Breaker and Service Disconnect
Switch shall be installed for the indoor equipment.
Note - The outdoor unit should have its own dedicated
Circuit Breaker and Service Disconnect as well.
• Indoor unit power supply MUST not be taken from the
outdoor unit.
• Fit the power supply wiring of each unit with a switch
and fuse as shown in the wiring diagram.
• Install an interrupter switch or ground-fault circuit
interrupter for the power wiring.
• Make sure the ground resistance is no greater than
100Ω. This value can be as high as 500Ω when using
a grounding fault circuit interrupter since the protective
ground resistance can be applied.

System Communication and Control Wiring

NOTE - Two-conductor shielded cable must be used for
the communication wiring. This is necessary to ensure
proper system communication and operation.
NOTE - High Voltage Cabling and Low Voltage Commu-
nication Cabling shall not pass/occupy the same electri-
cal port. All VRF/Furnace Communication cabling must
be 18 Gauge shielded/stranded.
System communication wiring is connected to the P and Q
terminals. See the Typical System Communication Wiring
diagram. See Figure 16.
Communication wiring between parallel AHU Control Kits
is connected to the X and Y terminals. See the Parallel
AHU Control Kit Configuration diagram.
Local controller wiring is connected to the
COM and 12V terminals to the first indoor unit and HA
and HB for all other indoor units connected to the same
controller. Reference and adhere to controller installation
instructions..
Fan Control wiring is connected to the Li, Mi and Hi
terminals (dry contacts) and 0, Vi (0~10V Input) terminals.
The input ports are described in the Fan Control Section.
NOTE - If multiple AHU Control Kits are connected in
parallel, the Main kit will maintain fan control.
1. Remove the screws that secure the control box cover.
Remove the cover and place it to the side where it will
not be damaged.
2. Locate the terminal strip in the control box. Connect
the power wiring (sized per NEC/CEC and local
codes) and communications cable (two-core, shielded
cable). Refer to unit nameplate for rated voltage.
3. Use the optional extension cable kit V0CTRL93P-1
(cat # 14R84) to locate the receiver/display a distance
from the control box.
Connect properly sized power wiring and two (system
communication) or
shielded communication and control cables as shown.
18
four-conductor (VRF controller)
HA, HB,