My thermostat only had two wires ran to it. I ran a separate wire to the "g" and back to the green wire on furnace but fan will not run. Am I missing something?

Did you kill the power to the furnace? If not you may have fried the transformer

Yes killed power. Furnace runs fine in "auto"

Remove power. First of all, check to see if you get the same behavior in heat and cool modes.

Second. Kill power. Remove G at tstat. Connect R to G at furnace.

Furnace runs fine in both modes. I just want to be able to only turn the fan on to move air around the house

No try fan only mode in both modes heat and cool

Quote:

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Originally Posted by rawlidog

My thermostat only had two wires ran to it. I ran a seperate wire to the "g" and back to the green wire on furnace but fan will not run. Am i missing something?

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Only 2 wires, so you don`t have ac added to heat system

If this is a heat only furnace, then the two wires that are supposed to be connected are W and R.

Tell me if this is a system where heat or cool is selected at the furnace.

Is a heat only system. W and r are connected.ran separate wire for g

Is there an Rc on your thermostat?

Please do as Kiss suggested. Jump r and g at furnace board, make sure you are holding in the blower door safety switch. If blower kicks on, then you have either a problem in the thermostat, or the new wire you ran. Please let us know what you find.

Yes

Rc in thermostat

OK, jump Rc to (Rh or R)

Jumped R to G at furnace fan came on

So how do I wire it so I can turn it off and on at thermostat?

Ok, we are getting close to the problem. One more test I need you to do for me, OK? Now jump r and g on the thermostat and let me know if fan comes on.

Please let me know if you are working on this as we speak, if so, I will stick around and help you get this figured out. IF you are not going to be around for awhile I may not be back till tomorrow.

Jump Rc to (R or Rh) at the thermostat permanently.

OK so I jumped r and g at the thermostat and fan did not come on.

Rh rc are already wired together at thermostat.

If it worked down, but not up then it has to be the connections.

Usually the fan is powered by the cooling circuit, so that's why I was pretty sure jumping Rc to Rh would work.

What is the brand of the thermostat?

Could the wire be broken?

Sorry I took so long to get back. If you jumped are and g at furnace and blower came on, then you jumped are and g wire at thermostat and blower did not come on, its as simple as this,, the new wire you ran to furnace is no good. By jumping at furnace, you bypassed thermostat and stat wireing. By jumping at stat, you bypassed the stat. Only thing left is the new wire. So here's what you do, run another wire and hook it to g at stat and g at furnace and I all put promise it will cure your problem. Make sure to use actuall themostat wire. Please let me know how you make out. Ill eat my hat if it doesn't work with another new wire. Good luck and please do let us know the outcome.