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Phil, Mechanical Engineer
Category: HVAC
Satisfied Customers: 6022
Experience:  Retired HVAC/ Electrical & Boiler contractor. Industrial
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i have a friend who has a problem with a lennox lf3e-110-1,he

Customer Question

i have a friend who has a problem with a lennox lf3e-110-1,he recently had a new ignitor installed and it worked for a little while,but now it is not.
Submitted: 7 years ago.
Category: HVAC
Expert:  Rick replied 7 years ago.
HiCustomerbr />

A typical furnace has the following sequence of operation
Thermostat calls for heat
Draft induction fan starts
Pressure switch proves draft
Pilot ignitor arcs
Pilot ignites flame sensor proves pilot flame
Or with a hot surface ignitor; ignitor glows
Gas valve opens burner ignites
Flame sensor proves burner ignition
Blower comes on

I need to know where in this sequence the unit fails