burners on for 3 seconds


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Old 03-28-11, 05:33 PM
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Exclamation burners on for 3 seconds

I cleaned the flame sensor. And still the burners light up then go out after 3 seconds
 

Last edited by hvactechfw; 03-28-11 at 06:20 PM. Reason: started new thread instead of hijacking an old thread
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Old 03-28-11, 06:11 PM
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My furnace is doing the same thing. I cleaned the flame sensor. And still the burners light up then go out after 3 seconds
without a meter to check the DC micro-amp flame signal it is hard to tell if you are sending the correct signal to the furnace control board. Flame sensors sometimes go bad. However it is usually due to excessive build up of carbon on the flame sensor.
 
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Old 03-28-11, 06:36 PM
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I got it to work for one cycle. Then it's back to shutting off in 3 seconds. Thanks for the reply. I'm thinking it might be the circuit board. I have an upstairs unit and a downstairs unit and I switched the flame sensors to see if maybe one was bad. They both worked on one unit. The led lights say everything is working normal.
 
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Old 03-28-11, 07:05 PM
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check the wires where connected to on the control board. Depending on your furnace the flame sensor may have its on connection on the control board. also check for proper ground to the gas manifold and burner assembly. also the face of the burners may need cleaned.
 
 

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