Operating instructions

SMB 09-0022 90% Furnace Inspection Instruction

To clean the blower assembly:

Disconnect power from furnace

Remove blower access panel

Disconnect blower motor wiring from furnace control board

Remove the control box from the furnace and set aside

Note: Before you begin the next step, the condensate trap and tubing will have water in

it. Use caution to avoid spilling water on electrical components

If the condensate trap is installed through the blower deck, remove the condensate trap

Remove the blower assembly from the furnace

Vacuum any loose dust from the wheel, motor and housing

If necessary, disassemble the blower assembly and clean each component separately.

Re-assemble blower assembly

Install the blower assembly in the furnace

Note: If condensate trap was removed, clean the trap before installing in the blower

deck. To clean condensate trap, flush thoroughly with warm water and shake dry.

Re-install condensate trap in blower deck and re-connect all tubing and hoses (if necessary)

Reconnect any wiring removed as part of the removal process

Re-install control box in furnace

Inspect all wiring and components for loose or missing wires

Re-install blower access panel

C. Cleaning burners

To clean the burners, it will be necessary to remove the burner box. Removing the burner box will

allow for inspection of the primary heat exchanger inlets in the next step. It is highly recommended

that a new burner box gasket be installed when re-installing the burner box.

Turn the gas supply off at the external shut-off

Disconnect the gas line from the gas valve. Use a back-up wrench on gas valve to prevent

twisting or rotating the manifold in the burner box

Disconnect the combustion air pipe from the air intake box

Disconnect pressure switch hose from combustion air intake box

Remove wires from the roll-out switch

Remove wires from hot surface ignitor

Remove wire from flame sensor

Remove two screws attaching top filler panel and rotate upwards to gain access to screws

attaching burner box to cell panel

Remove the remaining screws from the burner box

Remove the burner box from the furnace

Remove the burner box cover from burner box

Remove the following items from the burner box:

ignitor and bracket

manifold

burners

flame sensor

combustion air intake box