Page 37
LHT/LDT024, 036, 048, 060
FIGURE 25
BURNER BOX ASSEMBLY
GAS VALVE
GAS MANIFOLD
FLAME
SENSOR
BURNERS
IGNITOR
REMOVE INDIVIDUAL BURNERS ON
OLDER UNITS; REMOVE THE ENTIRE
BURNER ASSEMBLY ON NEWER UNITS.
FIGURE 26
IGNITOR
SPARK GAP
SHOULD BE 1/8”
(3mm)
D-Combustion Air Inducer (LDT Only)
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.
FIGURE 27
BURNER ORIENTATION
One- and Two-Stage Heat
150,000 BTUH - 7 BURNERS
108,000 BTUH - 5 BURNERS
65,000 BTUH - 3 BURNERS
SENSOR
IGNITOR
SENSOR
IGNITOR
SENSOR
IGNITOR
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 28.
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.
