8
SYSTEM CONTROLLER OPERATIONS – DIGI3U
HEAT PUMP OPERATION
The
DIGI3U
controller, when configured for Heat Pump operation,
allows the use of a standard Heat Pump thermostat (1 stage cool / 2
stage heat) to be connected to the
STAT 1
position on the controller.
Emergency Heat control is selected from the Heat Pump thermostat
wired to the
STAT 1
position. Standard Gas/Electric thermostats are
used for
STAT 2
and
STAT 3
positions.
Cool Mode with LAT:
When a thermostat makes a call for cool, Y, G, and
W-O/B LEDs and outputs to unit are energized. Any non-calling zone
dampers are energized to close. The cool call continues to operate unless
the supply air temperature drops below 45°, at which time the controller
will de-energize “Y” for approximately 3 minutes.
After 3 minutes, if the leaving air has risen above 45°, Y will energize,
restarting cool operations. When the cool mode is satisfied from the last
calling thermostat, W/OB remains energized until an opposite call for
heat is made.
If this controller is configured for “B” reversing valve operation, W-O/B LED
will not energize for cool mode; “B” energizes reversing valve in heating.
After all calls for cooling are satisfied Y, G and all damper LEDs will go
off and controller will initiate a 3-minute purge. During this time
controller will not allow a call for heat or cool.
Heat Mode with LAT:
When a thermostat makes a call for heat, Y & G
LEDs and unit outputs are energized. Any non-calling zone damper
LEDs and outputs are energized to close. The heat call will continue to
operate unless the supply air temperature rises above 120°, at which
time the controller will de-energize “Y” for approximately 3 minutes.
After 3 minutes, if leaving air is less than 120°, Y will reenergize and
heat will restart.
Auxiliary heat is energized after 3 minutes of run time and if the leaving
air temperature is 88° or less. The auxiliary heat will cycle off when the
leaving air temperature reaches 100°. When the controller energizes W2
to the heat pump strip heater, the W2 LED is illuminated. When all calls
for heat are satisfied, W, W2 ,G and damper LEDs will go off and
controller will initiate a 3-minute purge. During this time, controller will
not allow a call for heat or cool.
Configure DIGI3U for heat pump operations.
Place jumpers JP1 and JP2 in desired position: JP1 “O,” reversing valve for cooling (“B” position
will energize reversing valve in heating),
JP2 set in HP position
.
HEAT PUMP CONFIGURATION REQUIRES USING THE LAT SENSOR
