Lennox Rooftop Unit LGH074

Turn off the electrical power to the unit

Turn off the gas supply to the unit

Remove the burner compartment access panel

Remove screws securing burners to burner support

Lift the entire burner assembly from the orifices

Filter Inspection and Replacement

Check the condition of the filters

Is filter replacement necessary?

Take note of air flow direction marking on filter frame when reinstalling filters

Replace factory-installed filters within 30 days of initial unit start-up

Ensure filters are replaced with approved filters before building is occupied

Refer to local codes or appropriate jurisdiction for approved filters

Verify that temporary filters are replaced before building occupancy to prevent unit damage

Ensure all motors are lubricated at the factory

Verify that no further lubrication is required for factory-lubricated motors

Blower Shaft Bearings Lubrication

Check if blower shaft bearings are prelubricated

Is it time for the 2-year relubrication?

Select the grease to be used for relubrication

Use a hand grease gun for relubrication

Add grease until a bead appears at the seal lip contacts

Remove the combustion air inducer assembly as described in the Combustion Air Inducer subsection

Clean the flue box with a wire brush as required

Clean the tubes with a wire brush

Replace gaskets during reassembly

Inspect the following components for corrosion, deterioration, or debris deposits

Remove any obstructions or blockages found during inspection

Refer to Figure 5, Figure 6, or Figure 7 for detailed diagrams