HVAC blows cool air in the morning but warm in the afternoon
Posted 16 December 2013 - 12:03 PM
Thermostat calls for heat. 2. Draft inducer motor starts. 3. Pressure switch attached by a small plastic or rubber tube senses the negative pressure produced by the draft inducer and closes. 4. Draft inducer runs for 30 seconds to a minute before you hear a gas hissing sound. The ignitor did not glow, the flame sensor (a small metal probe about 1/8" in diameter, with a white porcelain base) does not sense the flame, so after 8 to 10 seconds the hissing sounds stops with no ignition of gas to heat your home. Your furnace shuts down and goes into a lock out condition until you turn your power switch back off and on again. Then the sequence starts all over again with no ignition of the gas.
The first day I did find the draft inducer was binding up and not spinning. After freeing this up with wd40 it has been working since. I have ordered a new one and will replace it when it arrives. Not sure what could be causing the heat not to work in the mornings. I suspect the colder temps lately have something to do with it but I don't know what component could be " cold sensitive" . Any help would be great!
Posted 16 December 2013 - 12:31 PM
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Posted 16 December 2013 - 12:36 PM
Posted 16 December 2013 - 01:12 PM
Posted 16 December 2013 - 10:11 PM
Posted 17 December 2013 - 07:38 AM
The sequence you describe is exactly what should happen when the igniter has failed.
Posted 17 December 2013 - 05:17 PM
You could unplug the ignitor and fire up the system with ohmmeter connected to the harness to see if power is getting tothe ignitor. If no voltage hunt down an open lmit and look for blocked stack or something else that would cause a limit to trip.
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Posted 19 December 2013 - 12:39 PM
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