Lennox HVAC Unit ML193UH110XE48C

Read and understand all safety warnings before proceeding.

Disconnect all electrical power to the furnace before servicing.

Label all wires prior to disconnecting them.

Reconnect wires correctly after servicing.

Verify proper operation after servicing.

Ensure the unit is properly grounded in accordance with national and local codes.

Use copper wire only. Do not use aluminum wire.

Size wiring and circuit breaker(s) per Product Specifications bulletin (EHB) and unit rating plate.

Read and understand all safety warnings before proceeding.

Disconnect all electrical power to the furnace before servicing.

Label all wires prior to disconnecting them.

Reconnect wires correctly after servicing.

Verify proper operation after servicing.

Exhaust and Air Intake Pipes Inspection

Check the exhaust and air intake pipes for tightness.

Ensure there is no blockage in the exhaust and air intake pipes.

Turn off electrical and gas supplies to the furnace

Use papers or protective covering in front of furnace while removing heat exchanger assembly

Mark all gas valve wires and disconnect them from valve

Remove gas supply line connected to gas valve

Remove sensor wire from flame sensor and disconnect 2-pin plug from the ignitor

Disconnect wires from flame roll-out switches

Have a shallow pan ready to empty condensate water

Remove the clean out cap from the condensate trap

Empty water from the condensate trap into the shallow pan

Inspect the condensate trap for any damage or blockages

Reinstall the clean out cap on the condensate trap

Turn off gas and electrical power to the furnace

Remove heating compartment access panel

Disconnect the gas supply line from the gas valve

Disconnect and label wires from gas valve

Disconnect ignitor wiring at 2 circuit plug

Disconnect and label wires from rollout switch

Disconnect and label flame sensor wire