Cs8500 Setup; Bacnet With M3 Unit Controller; Network Topology; Cs8500 Set Point Change - Lennox ComfortSense 8500 Series Installation And Setup Manual

CS8500 Setup

1. From the CS8500's home screen, go to MENU
> TECHNICIAN SETTINGS and enter 864 and
press OK to proceed.
2. Both the RTU and the CS8500 must be set
to the same S-Bus address. The rooftop
unit's default address is 2 unless it has been
changed. Set the CS8500 S-Bus address to
match the rooftop unit's S-Bus address.
3. Set operation with Smart Hub (central hub or
NCP) to ON/OFF.
• If the CS8500 is setup with the rooftop units
with a NCP set this to ON.
• If the CS8500 is setup with the rooftop units
and no NCP set this to OFF.
• If the CS8500 is being used in an iCON by
Lennox automation system with a Central
Hub, set this to ON.
NOTE: It may take 30 seconds up to two minutes
for the CS8500 to connect.

BACnet with M3 Unit Controller

This section describes how a CS8500 operates in a
BACnet environment with a M3 unit controller.

Network Topology

• All rooftop units are connected to the BACnet
front-end.
• Each rooftop unit is connected to one CS8500.
• The CS8500 communicates with the rooftop
units using the Lennox proprietary S-Bus
protocol.

CS8500 Set Point Change

The BACnet front-end provides the occupied and
unoccupied set points to the roof top unit.
The roof top unit (RTU) sends the same set points
to CS8500. The rooftop units uses these set points
until the CS8500 provides a new set point. When the
user changes the set point at the CS8500, it com-
municates the same to M3 unit controller. Upon re-
ceiving this information, the M3 unit controller starts
an override timer and uses the new set points until
the timer expires.
• While the timer is active, if BACnet queries the
M3 unit controller, it will be informed that the
rooftop units is using the override set points.
• When the timer expires, both the M3 unit
controller and CS8500 reverts to the set points
provided by BACnet.
10