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Verifying Burner Operation
WARNING:
Uninsulated live components are exposed when
louvered control access panel is removed.
1. Remove the louvered control access panel and verify
there is power to the unit.
2. Set thermostat above room temperature and observe
the ignition sequence. NOTE: The burner flame should
carry over immediately between all burners without
lifting off, curling, or floating. The flames should be blue,
without yellow tips. Make sure the flame is drawn into
the center of the heat exchanger tube. In a properly
adjusted burner assembly, the flame bends down and
to the right at the end of the heat exchanger tube. The
end of the flame will be out of sight around the bend.
3. After validating flame characteristics, set the thermostat
below room temperature and verify the burner flame
extinguishes completely.
Refrigerant Charging
WARNING:
These units are shipped fully charged with
R-410A refrigerant and ready for installation.
When a system is installed according to these
instructions,no refrigerant charging is required.
If repairs make it necessary for evacuation and
charging, it should only be done by qualified,
trained personnel thoroughly familiar with this
equipment. Some local codes require licensed
installation/service personnel to service this
type of equipment. Under no circumstances
should the owner attempt to install and/or
service this equipment. Failure to comply with
this warning could result in property damage,
personal injury, or death.
CAUTION:
This unit uses R-410A refrigerant. DO NOT use
any other refrigerant in this unit. Use of another
refrigerant will damage the unit.
The system refrigerant charge can be checked and
adjusted through the service ports provided at the front
panel. Use only gauge lines which have a "Schrader"
depression device present to actuate the valve. Draw a
vacuum on gauge lines to remove air before attaching
them to the service ports on the unit. Refrigerant charging
must be done by qualified personnel familiar with safe
and environmentally responsible refrigerant handling
procedures.
18
OPERATING SEQUENCE
The operating sequences for the heating, cooling, and
fan modes are described below. Refer to the field and
unit wiring diagrams (Figures 11 & 12, pages 27 & 28).
Heating Mode
1. On a call for heat, the thermostat closes and applies
24 VAC to the W terminal of the control board.
2. The control board checks for continuity on the 24 VAC
limit control circuit through the over-temperature limit
switch and flame rollout 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 valve
closes.
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