Planned Service
The following items should be checked during an annual inspection. Power to the unit must be shut off for the service techni- cian’s safety.
Fresh air grilles and louvers (on the unit and in the room where the furnace is installed) − Must be open and unob- structed to provide combustion air.
Burners − Must be inspected for rust, dirt, or signs of water.
Vent pipe − Must be inspected for signs of water, damaged or sagging pipe, or disconnected joints.
Unit appearance − Must be inspected for rust, dirt, signs of water, burnt or damaged wires, or components.
Blower access panel − Must be properly in place and pro- vide a seal between the return air and the room where the furnace is installed.
Return air duct − Must be properly attached and provide an air seal to the unit.
Operating performance − Unit must be observed during operation to monitor proper performance of the unit and the vent system.
Combustion gases − Flue products must be analyzed and compared to the unit specifications.
Problems detected during the inspection may make it nec- essary to temporarily shut down the furnace until the items can be repaired or replaced.
Instruct the homeowners to pay attention to their furnace. Situations can arise between annual furnace in- spections that may result in unsafe operation. For instance, items innocently stored next to the furnace may obstruct the combustion air supply. This could cause incomplete combustion and the production of carbon monoxide gas.
Repair Parts List
The following repair parts are available through independent Lennox dealers. When ordering parts, include the complete furnace model number listed on the CSA International nameplate −− Example: ML180UH045P24A−01. All service must be performed by a licensed professional installer (or equivalent), service agency, or gas supplier.
Cabinet Parts
Upper access panel
Blower panel
Top cap
Control Panel Parts
Transformer Integrated control Door interlock switch Circuit breaker
Blower Parts Blower wheel Blower housing Motor
Motor mounting frame Motor capacitor
Blower housing cutoff plate
Heating Parts
Flame sensor
Heat exchanger assembly Gas manifold Combustion air inducer Gas valve
Main burner cluster Main burner orifices Pressure switch Ignitor
Primary limit control Flame rollout switch (s) Secondary limit
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