Manual 2100-537
I
Page 38 of 54
BLOWER
Blower functions are all controlled through 24 VAC input
signals from the control thermostat and 208/230 VAC being
supplied to the motor continuously.
The installer must be sure to congure the tap select control
board (located in blower compartment) based upon the
specic model application. By default, the tap select control
(located in the blower compartment), is shipped from the
factory to operate at the airow ranges for the GTC60S2
model. Please see Wiring Diagram (Page 53) which details
the required dip switch changes required between models.
NOTE 1: On a call from only “G” from the thermostat (call
for manual fan), the blower will operate at a signicantly
reduced airow rate to allow for air circulation and
ltration, but at reduced power consumption and sound
levels.
NOTE 2: There are ±10% adjustments that are enabled
on the tap select control that will allow you to increase or
decrease the air volume plus or minus 10%. Increasing the
air volume may help with some slightly increased capacity
and increased duct velocity if there is an air distribution
issue. Decreasing the air volume with help improve latent
capacity in a humid application, and will help to lower air
distribution sound levels. Please see Wiring Diagram (Page
53) which details the required dip switch changes for this
adjustment.
PART LOAD COOLING
When thermostat system switch is placed in COOL,
it completes a circuit from “R” to “O”, energizing the
reversing valve solenoid. On a call for cooling, the
thermostat completes a circuit from “R” to “Y1” sending the
signal to both the Tap Select Control located in the blower
section and to the Geothermal Logic Control located in the
compressor section. The tap select control uses the input
signal versus the motor program, and the dip switch settings
to determine the proper air volume rate to operate. The
Geothermal Logic Control veries that the High Pressure
Switch, the Low Pressure Switch, and the Freeze Stat
controls are all in the “closed” position. It then energizes
the “A” terminal ouput to start the ow center (Ground
Loop Applications) or energizes the water solenoid (Ground
Water/Water Loop Applications). Following 10 seconds of
the “A” terminal energization, the compressor contactor is
energized.
FULL LOAD COOLING
The system should already be in Part Load Cooling
operation prior to Full Load Cooling being energized.
Additionally what happens, the thermostat completes a
circuit from “R” to “Y2”. This sends a signal to both the
staging solenoid on the side of the compressor, and sends
a signal to the Blower Tap Select Control in the blower
compartment to drive the blower to the proper CFM.
PART LOAD HEATING (No Electric Heat)
When thermostat system is placed in HEAT, the reversing
valve solenoid is no longer energized. On a call for part
load heating, the thermostat completes a call from “R” to
“Y1” sending the signal to both the Tap Select Control
located in the blower compartment, and to the Geothermal
Logic Control located in the compressor section. The
tap select control uses the input signal versus the motor
program, and the dip switch settings to determine the proper
air volume rate to operate. The Geothermal Logic Control
veries that the High Pressure Switch, the Low Pressure
Switch, and the Freeze Stat controls are all in the “closed”
position. It then energizes the “A” terminal output to start
the ow center (Ground Loop Applications) or energizes the
water solenoid (Ground Water/Water Loop Applications.)
Following 10 seconds of the “A” terminal energization, the
compressor contactor is energized.
FULL LOAD HEATING
The system should already be in Part Load Heating
operation prior to Full Load Heating being energized.
Additionally what happens, the thermostat completes a
circuit from “R” to “Y2”. This sends a signal to both the
staging solenoid on the side of the compressor, and sends
a signal to the Blower Tap Select Control in the blower
compartment to drive the blower to the proper CFM.
SUPPLEMENTARY ELECTRIC HEAT
The system should already be in FULL LOAD HEATING
operation (above). The thermostat completes a circuit from
“R” to “W2”, which energizes the rst bank of electric heat.
GEOTHERMAL LOGIC CONTROL
If the controller operates in normal mode, the green Status
LED blinks. This indicates that 24 volt power is applied to
the board and the controller is running in normal operation.
On initial power up and call for compressor operation, a
5-minute delay + a random start delay of 0 to 60-second
is applied. After the random delay, the compressor relay
is energized (Terminals CC & CCG). When the “Y” input
opens the compressor de-energizes.
Water Solenoid – When “Y” signal is sent to Geothermal
Logic Control, the water solenoid output “A” terminal
will energize 10 seconds prior to “CC” output that starts
compressor.
Anti-Short Cycle Timer – After compressor shutdown, or
power disruption, a 5-minute timer is applied and prevents
the compressor from operating.
SEQUENCE OF OPERATION
