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Discussion Starter · #1 ·
So. I am a carpenter by trade. My family is masons. Know the other trades, blah, blah, blah. the one trade Im useless at is hvac. so I made a custom barn door for someone and it was to hide things on her wall. one of those things was a thermostat. it stuck out of the wall so I replaced it with a smaller thinner Honeywell. hooked up the g the y the o and the r which is bridged to both r's. the old one had the black wire hooked up to the x but the new one said to bury it. "tested" it. the fan blew for both heat and a/c, the a/c worked, but got a phone call that the heat wasn't working. btw. it is a trane heat pump/ air handler in a condo. so I went there today and turned off the circuit and the switch that was wired onto the unit. I put the black wire to the b and turned everything on. nothing happened. turned everything off. dissconnected the black turned it back on. nothing happened. looked for the small amp fuse and I couldn't find one. so I crossed the g wire with the r wire and the fan didn't turn on. I'm guessing no power. the thermostat still was clicking but nothing was turning on. How bad did I screw things up?
 

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holy sheet....run quick she's gonna blow.....:thumbup:



me thinks you popped a fuse.

split system or packaged unit?


hopefully a hvac guy will stumble in here.....
 

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Discussion Starter · #3 ·
lol. I'm guessing a packed unit. compressor and wires on the side I can access. its about 4' long. and I couldn't find any fuses.
 

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in most cases you can wire the t stat the same as the unit control board. Just cause it says to put the red wire on the R terminal doesn't mean that the other end of the red wire is on the R terminal of the unit. Ya its supposed to be but is it? You likely didn't cook anything more serious than a fuse.
 

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Discussion Starter · #5 ·
the a/c and the fan worked before, just not the heat. Where would the fuse be located? I already looked where the wiring is, unless is a different kind of fuse? trane model gebh03011l210b0010000200000000000
 

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Black wire to b terminal on the stat, is likely the issue. When there is a call for heat, the b terminal is hot.... Rheem / Ruud gear energizes the Reversing valve in heat mode, thus the b terminal. Most equipment energizes the reversing valve in cool O. Perhaps the black wire should be on the C terminal on the new thermostat.

Not that big of an issue, if the air handler has a fuse. Still not too big of an issue, but, odds are its a blown control voltage fuse.


If this is greek, an hvac guy should make mince meat of this. I prefer hardwired stats as opposed to battery powered, or power stealing....Too much shop talk with that. :)
 

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BTW, remove the black wire from the B terminal, and then check the fuse. And / Or, make sure the furnace is off while messing with the thermostat wire. We have went to many service calls in which the big issue was a blown fuse while changing thermostats.... Due to working on a live circuit.
 

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Good chance you burned out the transformer when you connected the black wire(used as a common) to an energized terminal(B heat relay/reversing valve).

Did you program/set up the thermostat for operating a heat pump?

Post model number of thermostat.
 

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Discussion Starter · #10 ·
Thanks all for the help. it was the transformer. there was no fuse installed so I put one on for the future.
 

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No Kidding! People that work on their own gas systems really make me worry for their neighbors! As a painter I work as a jack of many trades BUT GAS!!?? Not this kid!
I think he's working on a thermostat, not the gas line, so I assume the neighbors made it through this fairly safely ;)
 
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