Page 40
LGT/LCT036, 048, 060, 072
D-Combustion Air Inducer (Gas Units)
A combustion air proving switch checks combustion air
inducer operation before allowing power to the gas
controller. Gas controller will not operate if inducer is
obstructed.
Under normal operating conditions, the combustion air
inducer wheel should be checked and cleaned prior to the
heating season. However, it should be examined
periodically during the heating season to establish an
ideal cleaning schedule.
Clean combustion air inducer as follows:
1- Shut off power supply and gas to unit.
2- Remove the mullion on the right side of the heat
section.
3- Disconnect pressure switch air tubing from
combustion air inducer port.
4- Remove and retain screws securing combustion
air inducer to flue box. Remove vent connector.
See figure 30.
5- Clean inducer wheel blades with a small brush and
wipe off any dust from housing. Take care not to
damage exposed fan blades. Clean accumulated
dust from front of flue box cover.
6- Return combustion air inducer motor and vent
connector to original location and secure with
retained screws. It is recommended that gaskets be
replaced during reassembly.
7- Replace mullion.
8- Clean combustion air inlet louvers on blower access
panel using a small brush.
HEAT EXCHANGER ASSEMBLY
Two-Stage Shown
FIGURE 30
BURNER
COMBUSTION
AIR INDUCER
VENT
CONNECTOR
GAS VALVE
HEAT
EXCHANGER
TUBE
PRIMARY
LIMIT
ROLLOUT
SWITCH
FLUE BOX
COVER
E-Flue Box (Gas Units)
Remove flue box cover only when necessary for
equipment repair. Clean inside of flue box cover and heat
exchanger tubes with a wire brush when flue box cover
has to be removed. Install a new flue box cover gasket
and replace cover. Make sure edges around flue box
cover are tightly sealed.
F-Evaporator Coil
Inspect and clean coil at beginning of each cooling
season. Clean the all-aluminum coil by spraying the coil
steadily and uniformly from top to bottom. Do not exceed
900 psi or a 45° angle; nozzle must be at least 12 inches
from the coil face. Take care not to fracture the braze
between fins and refrigerant tubes. Reduce pressure and
work cautiously to prevent damage. Flush condensate
drain with water, taking care not to get insulation, filters,
and return air ducts wet through entire cleaning process.
G-Condenser Coil
Clean condenser coil annually with water and inspect
monthly during the cooling season.
Clean the all-aluminum coil by spraying the coil steadily
and uniformly from top to bottom. Do not exceed 900 psi
or a 45° angle; nozzle must be at least 12 inches from the
coil face. Take care not to fracture the braze between the
fins and refrigerant tubes. Reduce pressure and work
cautiously to prevent damage.
H-Supply Air Blower Wheel
Annually inspect supply air blower wheel for accumulated
dirt or dust. Turn off power before attempting to remove
access panel or to clean blower wheel.
