Lennox furnace problem - please help


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Old 01-10-10, 11:24 AM
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Lennox furnace problem - please help

Hello, I have a Lennox high eff. furnace, 90UGF series, about 9 years old. One day it stops working. LED1 - slow alternate flash, LED2 - the same...Instruction book explanation - watchguard burners failed to ignite. I turn off the main switch, and turn it back on. It starts working - great!!! Flame is on, evertything is fine, but.... LED1 - slow flash, LED2 fast flash - explanation - replace flame sensor... Then the furnace worked for the whole night, but in the morning it's back to watchgurad, burners failed to ignite... so I turn it off and on again and it's starts working again..... Any tips on how to fix it? How do I replace flame sensor? Maybe just clean it? but How to get to it? Help please... Thomas K. Canada
 
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Old 01-10-10, 12:29 PM
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Clean the flame sensor, which is a rod sticking up into the flames on the opposite side of the furnace from the ignitor.
 
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Old 01-10-10, 01:26 PM
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Thank you, SeattlePionieer. When I was waiting for the reply, I went ahead and dismantled the furnace, got to the flame sensor and cleaned it..... Exactly what you suggested. It works fine so far.... Keep warm!
Thomas
 
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Old 01-10-10, 02:05 PM
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Like shooting fish in a barrel!


Manufacturers ought to include directions for cleaning flame sensors for that diagnostic light combination.


The other thing---- clean the flame sensor once/year. It should be routine annual maintenance.
 
 

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