SYSTEM OVERVIEW
ZonexCommander is a DDC system for automating and networking new
and existing stand-alone HVAC systems and mechanical devices.
The ZonexCommander networks 1-20 RTUs, AHUs, Heat Pumps, or split
systems per Command Center with an expansion capability of up to 80 units.
Gas Electric and Heat Pump HVAC units are controlled with communicat-
ing thermostats (DIGICOM / DIGIHP), while mechanical devices are
controlled with a relay device (RLYCOM). Each of these devices can be
scheduled through the simple Windows-based ZonexCommander
software and communicated to the Command Center via a daisy-chained
2-wire twisted pair communications link (Belden 8740).
The Command Center has available inputs for outside air temperature
display; and, with the addition of a SENDCOM sensor, each unit’s Return
Air and Supply Air temperature is remotely displayed on the Commander
software. This information may also be trend logged via the Zonex-
Commander Trending Program, included with your Commander software.
ZonexCommander allows you to instantly communicate and
remotely control every unit in your system.
OPERATION
The ZonexCommander Command Center polls all devices every minute
to register information on operation in the Command Center. DIGICOM
and DIGIHP thermostats place calls to HVAC units based on thermostat
setpoint.
Cool Call
The DIGICOM and DIGIHP thermostats will initiate a Y1 cool call when
the space temperature rises 1° above the Cool setpoint. The fan will also
be energized on “G.” On 2-stage systems, Y2 will be energized when the
space temperature rises 2° above the Cool setpoint. Y1 and Y2 will remain
energized until the active cool call is satisfied at setpoint.
When the DIGIHP thermostat is configured for “O” reversing valve on an
active cool call, “O” will energize on call for cool and will remain energized
until a heat call is made. When the DIGIHP is configured for “B” reversing
valve, there is no signal from the O/B terminal on an active cool call.
Heat Call
The DIGICOM and DIGIHP thermostats will initiate a 1st stage heat call
(W1 or Y1 & G) when the space temperature drops 1° below the Heat setpoint.
2nd stage heat is energized (W2 or Y2 & G) when the space temperature
drops 2° below the Heat setpoint. The DIGICOM thermostat does not
energize “G” for fan on a heat call unless the thermostat has been
configured for FAN ON in the Occupied mode.
On the DIGIHP thermostat, when the temperature drops 3° below the
heat setpoint, the auxiliary heat will be energized on W2 and G, along
with Y1 and Y2. When Emergency Heat is selected, Y1 and Y2 are
de-energized; and W2 and “G” are energized.
When the DIGIHP thermostat is configured for “O” reversing valve on an
active heat call, the O/B output will be de-energized. When the DIGIHP
is configured for “B” reversing valve on a call for heat, “B” will energize
the reversing valve and will remain energized until a call for cool is made.
Occupied/ Unoccupied
A schedule for Occupied and Unoccupied operation is made through the
ZonexCommander Windows-based software. This schedule will
communicate with thermostats to reset temperature setpoints of thermostats
for occupied and unoccupied time. Each thermostat can have its own
occupied and unoccupied schedule and thermostat setpoints. The Zonex-
Commander Windows-based software allows for seven-day programmability
with two occupied and two unoccupied time periods per day.
Thermostat Lock Feature
The DIGICOM / DIGIHP thermostats can be electronically locked
either individually or globally through the ZonexCommander program.
When a thermostat is in the Lock mode, the address number on the left
column of the Review screen on the Zonex software will be in red. The
thermostat will also display the Lock mode with a padlock symbol on the
upper left of the LCD display. When in the Lock mode, the thermostat can
be locally controlled providing heating or cooling changes ±2° from Heat
or Cool setpoint. The 2-hour override is operational in the Lock mode.
Schedule Override
The DIGICOM / DIGIHP thermostats provide a 2-hour override in the
Unoccupied mode. When the thermostat goes into the Unoccupied mode,
the backlight automatically goes off, and Unoccupied is displayed. When
the Select button on the thermostat is pressed in the Unoccupied mode,
the backlight energizes and the 2-hour override to Occupied begins. To
terminate the 2-hour override, press the Select button again, which
returns the thermostat to the Unoccupied mode.
schedule input on the Commander software. When the Command Center
Center sends an Unoccupied call, the RLYCOM de-energizes. Manual
SENDCOM
SENDCOMs work in conjunction with their assigned thermostats. To
review SENDCOM information, double click on an assigned thermostat’s
current room temperature. Supply and Return air temperatures will
appear on the REVIEW page for this SENDCOM, if a SENDCOM was
installed in this application.
ZONEXCOMMANDER SEQUENCE OF OPERATION
