24
gas flame has proven, the blower motor will slowly ramp
up to the selected motor torque. The blower will continue
to operate after the call for heat has been removed for 100
seconds.
NOTE:
All on- and off-delays for heating continue
to be controlled by the furnace control board.
Cooling or Heat Pump Mode
When the thermostat calls for cooling, the circuit between
R
,
G
, and
Y
is completed. The blower slowly ramps up to
the selected cooling motor torque.
Manual Fan
When the manual fan switch on the thermostat is on,
(energizing G only) the blower will operate on a default
setting of blower tap 1. Refer to
,
, &
and the Continuous Fan Blower Tap Setting section below.
Selecting Continuous Fan Blower Tap Setting
NOTE:
Power must be applied to the board or the unit can
be functioning to change the continuous fan speed.
1. Press the MENU button, the control will show the options on
the display. Keep pressing the MENU button, the options
are Err-L6F-Cr-Cod-OdU-HOd-COF-COP-HtP-rUn.
2. Blower taps 1-9 can be selected for the continuous fan
setting.
3. COF is the continuous fan mode blower tap setting. While
COF is on the LED display, press the OPTION button to
scroll through the selections for the continuous fan blower
tap settings.
4. Pres the OPTION button again and again to scroll through
the continuous fan blower tap settings. CF.1(Default),
CF.2,CF.3, CF.4, CF.5, CF.6, CF.7, CF.8, CF.9 will show
on the LED. Once the desired continuous fan blower
setting is displayed on the LED, press MENU to save the
selection.
NOTE:
Refer to (
,
,
) for air flow data.
Fault Conditions
There is a green and a red LED (labeled “Status”) on the
furnace control board to provide system faults as described
board fault conditions.
Electronic Air Cleaner (EAC)
The EAC relay is energized 5 seconds after the blower is
running and de-energized after the blower stops. The EAC
has dry contacts, therefore power will need to be supplied
to one side of the EAC terminal.
Humidifier (HUM)
The HUM relay is energized when a flame has been detected
and the blower is running. The HUM relay is de-energized
when no flame is detected. The HUM has dry contacts,
therefore power will need to be supplied to one side of the
HUM terminal
OPERATING SEQUENCE
The operating sequences for the heating, cooling, and fan
modes are described below. Refer to the field and furnace
wiring diagrams:
,
,
Heating Cycle
1. The thermostat calls for heat by energizing the W terminal
with 24VAC.
2. The control checks the HLI input for a closed limit.
3. The control performs a circuitry check and verifies the
that all 3 pressure switches are open. If any pressure
switches are closed during this check, the control will
monitor and wait for 30 seconds for them to open. If the
pressure switches are still closed after 30 seconds the
LED will show error codes of 3.1 and 3.3. If both pressure
switches are open during this check the control will cycle
through the next circuitry check.
4. The control continuously monitors the gas valve circuitry
to verify the gas valve relay and presence of voltage at
the valve. If there is a voltage detected at the gas valve
without a call for heat, error 7.1 will be displayed.
5. After a successful pressure transducer circuitry check, the
system will energize the inducer motor. Control monitors
the voltage from the pressure transducer but ignores low
voltage before the inducer is activated. Once the inducer
is activated, a voltage from the pressure transducer
.2 volts or less is considered low and will show a 4.1
Error code. If the voltage is between .2 and .7 volts and
pressure switch #1 fails to close at a call for heat, Error
3.2 is reported.
6. Once the inducer energizes, voltage between .2 and .7
is detected, and the-.5”WC pressure switch is detected
closed, the inducer 30 pre-purge begins.
7. The inducer will ramp down to 400 RPM.
8. After the completion of the pre-purge, the control will start
the 20 second igniter warm-up period.
9. After completion of the ignitor warm up period, the 4
second trial for ignition period begins.
10. The gas valve is energized. Flame failure response is
set at (2.5 seconds).
11. The ignitor is de-energized as soon as flame is sensed,
or at the end of the ignition activation period(IAP) of 2
seconds.
12. When the flame is sensed , the blower heat on delay
begins.(25s) and the inducer will start to ramp up.
13. The control will start monitoring the -.95”WC and -2.4”WC
pressure switches for closure.
• For the A050, the time delay to monitor the -.95”WC
and -2.4”WC pressure switches is 20 seconds after
flame sense.
• For the C100, the time delay to monitor the -.95”WC
and -2.4”WC pressure switches is 31 seconds after
flame sense.
14. When the thermostat is satisfied, the gas valve immediately
de-energizes and the heat off delay of 100(Default)
seconds begins.
15. The inducer output remains on for a 30 second post-purge
period.
16. If the call for heat is lost while the control is in the trial for
ignition period without flame being detected, the control
will turn off the gas valve and ignitor. The control will enter
the post purge routine of 60seconds. After completing
the post purge, the control will resume normal operation.
