Spent 4 hours installing a smart thermostat because my HVAC is from 1989

I don't know if it's just my house or what but the wiring was complete nonsense. The old thermostat had wires going everywhere and half the labels were rubbed off. Called my buddy who does HVAC and he laughed at me. Said most houses built before 2000 will fight you on this stuff. Finally got it working but I had to rewire the whole base plate three times. Has anyone else dealt with a house that just refuses to cooperate with modern tech?

3 comments

3 Comments

susanm5613d ago

My 1992 furnace had blue wires that were actually red, and a green wire that did nothing. I literally just guessed on the last two connections and crossed my fingers. Still not sure it's wired right but hey, it works!

reese12413d agoMost Upvoted

Hope you took a picture before you touched anything. That sounds like someone messed with the color coding decades ago and nobody ever fixed it. You probably got lucky - most old furnaces are pretty forgiving as long as you match the terminals right. But that green wire doing nothing is a pretty big red flag, could be a grounding issue or a hack job someone did. I'd check the voltage on that thing before winter hits hard, just saying.

bennett.vera5d ago

Three houses I've worked on had that same mystery green wire thing @susanm56 mentioned. It's always just sitting there loose in the wall, no connection on either end. Makes me think builders back then had a bulk deal on green wire and just ran it everywhere for fun. This stuff is like the Wild West of home improvement.