I have basic two wire thermostat, one for power on for neutral. I only have central heat, not air. My blower fan kicked on the last two sundays, but itself, but not today which is sunday. It only happens on sunday. My thermostat is programmable but I cannot use those features as it only has two wires going to it. Is there any explanation why this is happening? It's just something that is bugging me because it doesn't make any sense.

Thanks in advance.

  • Maybe a hidden/default program in the thermostat. Does the thermostat have batteries in it?
    – JACK
    Aug 8 '21 at 16:44
  • The wires are probably not common and neutral. they are probably R and W. R would be a 24V version of "power" and W would be "call for heat". There aren't any other wires. There is no "call for blower". If the blower is running, heat is on. Why would a thermostat want heat on? Aug 8 '21 at 16:57
  • Yes the thermostat has batters, they were old and crappy batteries. I changed the batteries and it didn't come on today. It's just weird that it was coming on only sunday mornings and no other time. If it was bad batteries wouldn;t it just be coming on randomly and not just sunday mornings?
    – Evan
    Aug 8 '21 at 17:34
  • I changed the batteries and it hasn't happened. Maybe it was just something with bad batteries. Just weird how it would come on at the same time every week and the thermostat is wired t be a programmable thermostat.
    – Evan
    Aug 8 '21 at 17:53
  • Is it getting hot in your house at all...? a 2-wire stat means that the furnace has to switch the blower on/off on its own, and it does that through a thermostat in the plenum/bonnet of the furnace -- if that plenum 'stat/limit's on the fritz, it'd explain seemingly spontaneous blower operation Aug 8 '21 at 18:31

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Browse other questions tagged or ask your own question.