just_wondering
Jun 21, 2009, 10:23 AM
Gas furnace is about 32 years old. This summer I noticed that switching the Fan to run in manual mode, 90% of the time it will not turn on. Suspecting the thermostat, I installed a new 7-day programable type. 1st time I tried manual fan it worked ok. Most of the time fan will not turn on using the manual 'on' mode. Here's the strange part, if I turn on the A/C in the Auto mode, the fan so far has never failed to run. How can the fan never fail to start when running the A/C but when I only want to run the fan, it usually doesn't start? If I play with the manual switch I may get lucky and it starts. Wiring connections are clean and tight. At first I thought the fan switch on the old thermostat was intermittent, so I installed a new thermostat. Any ideas would be greatly appreciated. Thank you!