STATUS LEDs
Y1 Y2 G W1 W2 PWR DPR MODE FUNCTION
OFF OFF OFF OFF OFF OFF OFF Off Power off
OFF OFF OFF OFF OFF ON OFF On Power on, blower off, all zone dampers open
OFF OFF ON OFF OFF ON 0 Vent Blower on, compressor(s) off, all zone dampers open
OFF OFF OFF OFF OFF ON 1 Purge Blower off, compressor(s) off, Dampers with LEDs on are closed
ON OFF ON OFF OFF ON 1 Y1 Cool 1st stage cool, blower on. Dampers with LEDs on are closed
ON ON ON OFF OFF ON 1 Y2 Cool 2st stage cool, blower on. Dampers with LEDs on are closed
OFF OFF OFF ON OFF ON 1 W1 Heat 1st stage heat, blower on. Dampers with LEDs on are closed
OFF OFF OFF ON ON ON 1 W2 Heat 2st stage heat, blower on. Dampers with LEDs on are closed
OFF OFF ON ON ON SFL 1 Cap cut out Blower on, all compressors off. Dampers w/LED on are closed
ON OFF ON OFF OFF FFL 1 Stage 2 cut out Compressor 1 on, blower on, damper w/LED on are closed
STATUS LED LEGEND
FFL
= Fast Flash
SFL
= Slow Flash
1
= One or more damper LEDs on
0
= All dampers LEDs are off
6
SYSTEM CONTROLLER – GAS/ELECTRIC
OPERATION
SYSTEM CONTROLLER - GAS/ELECTRIC
The DigiTract Controller is the heart of the DigiTract zoning
system. It is an auto changeover, home run system with built
in staging and capacity controller. The function of the
system controller is to receive calls from the zone thermo-
stats, operate the HVAC system in either heat or cool mode
and close the damper(s) of zones not calling for the operat-
ing mode. The mode of operation is determined by the first
call received. If the thermostats are calling for opposite
modes, a changeover sequence will start. Based on the
Time Setpoint setting, a changeover will occur after time
delay. Changeover will continue as long as there are oppos-
ing calls. The built in Capacity Contoller maintains the
supply air temperature within an operation range to prevent
freeze ups and overheating.
For Heat Pumps, the System Controller will also control the
auxiliary heat.
The Digitract 4 controller is not to be subjected to tempera-
tures below 33°F or above 160°F. The controllers must not be
installed in atmospheres that could create condensation or
corrosion. Warranty is voided on controllers that fail due to
moisture or corrosion evidenced on the circuit board. The
operating voltage range on the Digitract 4 controllers is 24
vac to 28 vac.
NOTE: For Heat Pumps systems using gas electric inputs
(“O” or “B” reversing valve circuits) use gas electric setup.
The System Controller will initially run in the mode request-
ed by the first calling zone thermostat.
Cool mode
- When running in the cool mode, the System
Controller energizes the compressor(s) and indoor blower.
This is indicated by the corresponding Y and G LEDs illumi-
nating. Dampers for the zones not calling for cool are
powered closed and the dampers for the zones calling for
cool are left open. This is indicated by the DPR LEDs. If the
DPR LED is illuminated on the damper terminal strip and the
damper terminal board, the corresponding damper is
closed. The system will continue to run in the cool mode
until all calls are satisfied or changeover occurs. When all
calls are satisfied or prior to changeover, the system will go
into a purge mode.
Heat mode
- When running in the heat mode, the System
Controller energizes the heat stage(s), indicated by the W
LEDs illuminating. Dampers for the zones not calling for
heat are powered closed and the dampers for the zones
calling for heat are left open. This is indicated by the DPR
LEDs. If the DPR LED is illuminated on the damper terminal
strip and the damper terminal board, the corresponding
damper is closed. The system will continue to run in the heat
mode until all calls are satisfied or changeover occurs.
When all calls are satisfied or prior to changeover, the
system will go into a purge mode.
Changeover
-
While the system is operating in one
mode, and the System Controller recives a call for the oppo-
site mode, the System Controller will continue to run in the
current mode until the changeover TIME limit has been
reached, or all current calls have been satisfied. Now the
System Controller will go into a purge mode for 4 minutes,
then changeover to the new mode.
Purge mode
- Purge mode is initiated after the last calling
zone is satisfied, or when the controller goes into a forced
changeover. All HVAC output LEDs on the controller go off
during this cycle. When the last calling zone thermostat
satisfies, the Digitract controller goes into a 4 minute purge
cycle. During this time delay all outputs to the HVAC system
and dampers are terminated. All dampers go to a full open
position and the HVAC system fan delay runs the blower for a
time. This time delay with no control outputs allows the supply
duct to return to ambient temperature before the next call is
initiated.
When the controller goes into a force mode changeover, and
the initial call drops out to the purge cycle, the HVAC outputs
are terminated, and the initial zone damper remains open for
a 4 minute delay with the other dampers closing. The HVAC
system fan control allows the blower to run for a time, and the
initial calling zone supply duct returns to ambient tempera-
ture.
Ventilation
- When no zones are calling, all zone dampers
are open. During this time, if any thermostat has the fan switch
ON then the indoor blower is energized (G made to R) and G
LED is on. This provides ventilation to all zones.
