Furnace Type: York Affinity 97% Efficiency
Installed: March 2009
Location: San Diego, California
This unit is to set to come on early mornings around 5:00 a.m.
Sometimes the indoor blower motor runs continuously (20-40 minutes) during the "call" for heat,
with no burners lit.
Due to the problem, a lot of parts were replaced, except for the following:
So the above still are originals.
When the problem occurs, I turn the heat to "off" and let it sit for a minute or two.
This apparently resets the unit.
Then I turn the unit back on to "heat" and that usually takes care of the problem because the unit then begins blowing hot air.
We originally thought there might have been some kind of RF interference caused by the installation a few years ago of a SMART utility meter installed by San Diego Gas & Electric, but if that was the case, the problem most likely would keep occurring throughout the day and not just in the early mornings when the unit first comes on.
This has been a real on-going mystery.
I believe the problem first started happening in 2010, about a year after the installation.
San Diego, California