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Old 01-29-2010, 06:14 AM   #1
Join Date: Dec 2008
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Furnace not kicking on

I'm not sure what the issue is here. For the last two days, I've woken up and it's been really cold in the house. This morning, I just woke up and the temp was 66 (thermostat set to 68) - I turned the heat off and back on and it didn't go on, so I have had to physically reset my furnce to get it to go back on. I saw the red lights flashing on the furnace each time. If I'm reading the code correctly, it's locking out because of ignition failure. We had to replace the ignitor in 2008 and the same thing was happening, so I think this may be the problem, How long do ignitors last? (We bought the house in March '06 and there's a note on the furnace saying the ignitor was also replaced in February '06) -- so if it the ignitor this would be ignitor # 3 (10 yr old house)

For some reason this is only happening overnight, which doesn't make sense.... I have replaced the thermostat batteries as well and the thermostat is still making this intermittent clicking sound...so I don't know if this means my thermostat is going bad or what. Thermostat is only 2 years old.

Help please...


Last edited by mterracciano; 01-29-2010 at 06:32 AM.
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Old 01-29-2010, 07:23 AM   #2
Join Date: Jan 2010
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i would need a little more info about your system. I am assuming you have a condensing gas furnace. how cold is it getting at night? if it is getting real cold your drain could be freezing up outside. do you have a condensate pump? or gravity drain? where do your flue pipes (exhaust & intake) terminate? on the side of your house or through the roof? i have seen the exhaust pipe freeze at the very end also?

try to determine the sequence of operation.

1.inducer motor startup
2.pressure switch verify's draft
3.ignitor startup
3.gas valve open
5.flame sensor verify's flame
6.end of call
7.gas valve closes
8.post purge inducer
9.blower shuts down

reset the power and have another call for heat and watch the operation.
if only the draft inducer runs and nothing else you have adraft problem which depending how cold it is getting could be your problem


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