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Normal Sequence of Operation
Power Up
Upon being powered up, the control board will perform in
-
ternal and polarity checks. The control will display I d L, idle
mode until a call from the thermostat is received.
Continuous Fan Mode Speed Selection
When a 24 vac signal is present on the G terminal, the blower
motor will operate on selected continuous blower speed. The
EAC-H will also be energized as long as the blower motor
is energized.
When the R to G circuit is opened, the blower motor will shut
down if no other function requires blower motor operation.
To change the main blower speed in circulation mode, follow
the following steps:
1. Press left or right switch until LED displays “F S d “. Press
center switch and the LED will display the selected speed
number as Fxx (xx: Blower speed number from 01 to 09).
SP3 is default speed for circulation.
2. The control will display an available speed number every
time Left/Right switches are pressed. All 9 speeds are
available for circulation.
3. Press the center button to select the desired speed. The
control will immediately apply that speed setting.
THERMOSTAT
CALL
AVAILABLE
SPEEDS
G
SP1
SP2
SP3 (DEFAULT
SP4
SP5
SP6
SP7
SP8
SP9
HeAtinG mode SPeed SeleCtion
To change the main blower speed in HEATING mode, follow
the following steps:
1. Press left or right button till LED displays “gA1 “(for single
stage HEATING) or “gA2 “(for Two stage HEATING).
Press center button and LED will display the selected
speed number as Fxx (xx: Blower speed number).
2. The control shall rotate available speed number every
time Left/Right switches are pressed. Table below shows
the available speeds for Low & High heat mode.
3. When the center switch is pressed, the current displayed
speed shall be selected, and control shall the newly
selected speed in next heating call.
Note:
Always refer to the Heating Chart to choose from
available heating speeds.
THERMOSTAT CALL AVAILABLE SPEEDS
W/W1
F01 (DEFAULT)
F03
F04
W2
F02 (DEFAULT)
F04
F05
Heating Mode
Call for 1st Stage Heat
•
On a call for heat, the thermostat contacts close & the
control board receives 24 vac on the W1 terminal.
•
The control board microcomputer runs its self-check
routine.
•
The control verifies the limit switch is closed (24 vac on
Pin 8 of the 12 Pin connector).
•
The control verifies that pressure switch circuit is open
(0 vac on Pin 5).
•
The control module performs a gas valve circuitry check
to verify gas valve relay state and presence of voltage
at the valve.
•
The system will energize the Induced draft blower.
•
The pre-purge period begins once the low fire pressure
switch is detected closed. (24 vac on Pin 5).
•
After the completion of pre-purge, the control will ener
-
gize the igniter.
•
After completion of the igniter warm-up period:
•
The gas valve is energized.
•
The igniter is de-energized as soon as flame is sensed.
•
After 30 seconds the indoor blower is energized on
heating speed.
•
When using a single-stage heating thermostat the fur
-
nace will transition to 2nd stage gas heat by either a
fixed time or auto mode, depending on menu selections
made by the installer.
•
The inducer motor is enabled at high speed.
•
Closure of the second stage pressure switch will energize
the high fire stage of the gas valve.
•
The 2nd stage gas heat speed of the indoor blower is
energized
