18
2. Remove the regulator cap. Turn the high fire adjusting screw
clockwise to increase the pressure or counterclockwise to
reduce the pressure.
3. Replace the regulator cap after adjustments are complete.
OPERATING SEQUENCE
The operating sequences for the heating, cooling, and fan
modes are described below. Refer to the field and
.
Heating Mode
1. On a call for heat, the thermostat closes and applies 24
VAC to terminal
W
on the control board.
2. The control board checks for continuity on the 24 VAC limit
control circuit, over-temperature limit switch, flame rollout
switches, and blocked vent switch in series. If an open limit
is detected, the control board will energize the inducer
blower. All other system functions will be inoperable until
the limit circuit closes. While the limit is open, the red LED
will pulse at a rate of 1 blink per unit time.
3. The furnace control checks for continuity (24 VAC) across
the pressure switch. If the pressure switch is closed, the
heat mode sequence will not continue. If it remains closed
for 10 seconds, the red LED will flash 3 times repetitively
until the fault condition clears.
4. The inducer energizes (if pressure switch is open).
5. The pressure switch will close. If the pressure switch does
not close after 10 seconds, the fault LED will flash 2 times
and the inducer will continue to run until the switch is closed.
6. The inducer will pre-purge for 30 seconds and then the
igniter will start its warm-up as follows:
Initial Power up:
After 30 seconds of igniter warm-up, the
gas valves (24 VAC) will open. The igniter circuit will stay
energized for 3 seconds after the gas valve opens.
After Initial Power up
: The control has a programmed adaptive
ignition feature which varies the warm-up period as follows:
If ignition is successful the warm-up is reduced by 3 seconds
on each subsequent call for heat until ignition failure occurs.
Upon ignition failure, the warm-up is increased by 3 seconds
on the next try. If successful, the timing remains fixed at
this level. In general, whenever ignition failure occurs the
warm-up interval is increased by 3 seconds on the next try.
And if successful, it remains there. Minimum and maximum
warm-up time limits are set at 6 and 54 seconds.
7. The furnace control must prove flame via the flame sensor
5 seconds after the gas valves open. If flame is sensed,
burners are on and the igniter cools off. If no flame is sensed,
the gas valve closes immediately and the inducer continues
to run. A second trial for ignition (step 6) begins. If no flame
is sensed on the fifth try for ignition, the furnace control is
locked and the red LED will blink 4 times repetitively. The
thermostat must be opened for at least ten seconds to reset
the furnace control after a lock out. Otherwise, the furnace
will attempt another ignition sequence in 1 hour.
8. After the gas valve opens (30 seconds), the blower will ramp
to the selected airflow and continues to run.
9. When the thermostat has been satisfied, the
W
terminal on
the integrated control is de-energized.
10. The gas valve circuit is de-energized and the gas vallve
closes.
11. The inducer motor will continue to run for the post purge
period of 25 seconds.
12. The main blower will continue to run for the BLOWER OFF
delay of 135 seconds.
13. After the BLOWER OFF timer has been satisfied, the
integrated control de-energizes the main circulating blower
circuit.
Cooling Mode
1. On a call for cooling, the thermostat closes and applies 24
VAC to the green and yellow leads in the low voltage area.
2. The green lead applies 24VAC to the
G
terminal of the
integrated control, energizing the main circulating blower
circuit at the cooling speed.
3. The yellow lead applies 24VAC to the contactor.
4. When the thermostat is satisfied, the contactor and integrated
control de-energize.
5. The circulating blower motor de-energizes after a 85-90
second delay.
Fan Mode
1. On a call for fan operation, the thermostat applies 24 VAC to
the green lead connected to the
G
terminal of the integrated
control.
2. The circulating blower is energized immediately at the
heating speed if 2-SPD is selected or fan only speed if
3-SPD is selected on the control.
NOTE:
If a call for heat
occurs, the circulating blower de-energizes prior to normal
heating cycle.
EQUIPMENT MAINTENANCE
WARNING:
ELECTRICAL SHOCK, FIRE OR
EXPLOSION HAZARD
Failure to follow safety warnings exactly could
result in serious injury, death or property damage.
Improper servicing could result in dangerous
operation, serious injury, death or property
damage.
• Before servicing, disconnect all electrical power
to furnace.
• When servicing controls, label all wires prior to
disconnecting. Reconnect wires correctly.
• Verify proper operation after servicing.
AVERTISSEMENT:
RISQUE D’ÉLECTROCUTION, D’INCENDIE
OU D’EXPLOSION
Si les consignes de sécurité ne sont pas suivies à la
lettre, cela peut entraîner la mort, de graves blessures, un
fonctionnement dangereux ou des dommages matériels.
Un entretien inadéquat peut entraîner la mort, de
graves blessures, un fonctionnement dangereux ou
des dommages matériels.
• Avant de faire l’entretien de l’appareil de chauffage,
le débrancher de l’alimentation électrique.
• Avant l’entretien des commandes, étiqueter tous
les fils avant de les déconnecter. Rebrancher
correctement les fils.
• Vérifier que l’appareil fonctionne correctement après
l’entretien.
