24
13.
When all heat exchanger tubes have been cleaned,
any debris inside the tubes can be removed with the
nozzle of a vacuum cleaner.
14.
With a light, check the condition of the upper and
lower sections of the heat exchanger tube.
15.
Inspect the burners and clean them (if necessary)
with a soft wire brush and/or the nozzle of a vacuum
cleaner. BE EXTREMELY CAREFUL NOT TO
DAMAGE THE IGNITOR WHILE CLEANING THE
BURNER.
16.
Replace all the parts in reverse order from which they
were removed.
17.
Follow the operating instructions found on the right
side door and the User’s Information Manual to return
the unit to operation.
Cleaning of Burners — If the burners must be cleaned,
follow the steps below.
1.
Shut off the gas supply to the unit either at the meter
or at a manual valve in the supply piping.
2.
Turn off all power to the unit and set the thermostat
to the lowest temperature setting.
3.
Remove the louvered control access panel from the
unit.
4.
Turn the gas control knob to the “OFF” position.
5.
Disconnect the wires from the gas valve, ignitor, and
flame sensor.
6.
Using wrenches, separate the ground-joint union in
the gas supply piping at the unit.
7.
Remove the piping between the gas valve and the
ground-joint union, if necessary.
8.
Remove the screws that hold the burner assembly in
place and remove the burner assembly. BE
EXTREMELY CAREFUL NOT TO DAMAGE THE
IGNITOR WHILE REMOVING THE BURNER
ASSEMBLY.
9.
Inspect the burners and clean them (if necessary)
with a soft wire brush and/or the nozzle of a vacuum
cleaner. BE EXTREMELY CAREFUL NOT TO
DAMAGE THE IGNITOR WHILE CLEANING THE
BURNER.
10.
Replace all the parts in reverse order from which they
were removed.
11.
Follow the lighting instructions found on the lower
unit door to return the unit to operation.
!
CAUTION:
Verify proper operation after servicing.
Operating Sequence
The operating sequences for the heating, cooling, and fan
modes are described below. Refer to the wiring diagram for
the unit (Figure 10).
Cooling Mode:
1.
On a call for cooling the thermostat closes, applying
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 anti-short
cycle timer if installed and then to the contactor.
4.
When the thermostat is satisfied the contactor and
integrated control are de-energized.
5.
The circulating blower motor is de-energized after a
90-second delay.
Blower 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.
3.
If a call for heat occurs, the circulating blower de-
energizes prior to normal heating cycle.
Heating Mode:
1.
On a call for heat the thermostat closes, applying 24
VAC to the “W” terminal on the integrated control.
2.
The integrated control monitors the safety circuit at
all times. If either the roll-out control or the over-
temperature limit control opens, both the main