I have a 10 year old Carrier furnace. When in heat/ac mode the fan will work, but it won't run continuously in "on" mode. When the heat/ac is "off", and the fan is "on", it won't work at all. It used to work continuously when in "on" mode. The blower motor was replaced a few months ago and the problems started then. The LED light is not showing any problems. Is there a quick fix?
Carrier furnace fan won't switch on
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Oh sorry, sometimes I assume too much.
Take a piece of wire and strip the two ends.
Touch one end to the "R" terminal and the other end to the "G" terminal on the thermostat terminal strip inside the furnace.
As I mentioned, there may be a safety switch that will kill power to the unit when the access panel is removed. For the most part, you can just hold this in to restore power while testing.
Jumpering the R&G should run the blower motor.
Take a piece of wire and strip the two ends.
Touch one end to the "R" terminal and the other end to the "G" terminal on the thermostat terminal strip inside the furnace.
As I mentioned, there may be a safety switch that will kill power to the unit when the access panel is removed. For the most part, you can just hold this in to restore power while testing.
Jumpering the R&G should run the blower motor.
What would I be achieving by doing this? I'm reluctant to try anything without knowing why I'm doing it. The blower motor does work if it's in heat mode, just doesn't stay on continously even tho the fan setting on the thermostat is set to "on".
I'm trying to guide you in troubleshooting the circuitry of the unit. This will basically tell us if the T-stat is bad or if there are other issues preventing the fan from working in the "On" setting. It's only 24VAC so no safety issues to be concerned about. If you prefer an alternate technique, you'll need a voltmeter. Turn your tstat to fan "On" and check for 24VAC from ground to "G" (green). This will tell me if the tstat is energizing the fan circuit or we can just energize it and see if the fan comes on which is what I was attempting in my prior post.
If the fan turns on as a result of the test, it will either be a bad Tstat or the wiring from the Tstat to the furnace.
If you'd like, you can jumper the R & G terminals on the back of the Tstat and this will verify the wiring and result in determining a bad Tstat.
If you'd like, you can jumper the R & G terminals on the back of the Tstat and this will verify the wiring and result in determining a bad Tstat.
Wuzzat?
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I think it's somewhat more likely that the problem is at the furnace end.
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What this tells us is that you could possibly have a bad wire from thermostat to furnace.
You'll have to jumper the R & G terminal at the furnace and see if the blower comes on.
Inside the furnace you'll see a wire coming in from the tstat.
Most likely brown insulation containing multiple colored wires.
What the thermostat does is completes a circuit of 24VAC from the R terminal to the G terminal to energize the fan circuit when fan "on".
If the G wire is bad, then power won't make it back to the furnace from the tstat. So now we must energize the G terminal at the furnace to eliminate this possibility. Inside the furnace you'll see the brown wire and it's multi-colored wires attach to the various terminals to run heat, A/C, fan, etc.
Touch the jumper wire to the R & G terminal and see if the fan comes on.
You'll have to jumper the R & G terminal at the furnace and see if the blower comes on.
Inside the furnace you'll see a wire coming in from the tstat.
Most likely brown insulation containing multiple colored wires.
What the thermostat does is completes a circuit of 24VAC from the R terminal to the G terminal to energize the fan circuit when fan "on".
If the G wire is bad, then power won't make it back to the furnace from the tstat. So now we must energize the G terminal at the furnace to eliminate this possibility. Inside the furnace you'll see the brown wire and it's multi-colored wires attach to the various terminals to run heat, A/C, fan, etc.
Touch the jumper wire to the R & G terminal and see if the fan comes on.
That's curious, based on what your telling me the fan should work when switched to "On".
We are going to have to back it up a step as I can't readily affect a repair online.
I need to know what wires (color) are attached to what terminals on both the furnace and thermostat. Watch for crossed wires where the color and terminal does not match the opposite end (furance vs. tstat).
Just to be sure, this is not a heat pump system; correct?
We are definitely closing in on the problem but, I need more info to complete the picture.
We are going to have to back it up a step as I can't readily affect a repair online.
I need to know what wires (color) are attached to what terminals on both the furnace and thermostat. Watch for crossed wires where the color and terminal does not match the opposite end (furance vs. tstat).
Just to be sure, this is not a heat pump system; correct?
We are definitely closing in on the problem but, I need more info to complete the picture.
This is not a heat pump system, just forced air gas. I've noticed that the wires hooked up to the thermostat and then reappearing at the furnace don't match. On the thermostat there is an unattached blue wire, and attached white, yellow, green and red all attached to the correct terminals.
At the furnace, the thermostat wires are red attached to red, black attached to Y/Y2, white attached to W/W1, blue attached to green, orange attached to nothing.
I noticed that the green wire does not come from the tstat wires, it's in a separate bunch of wires of all colours. However, it's connected to the G terminal and there's another connection to the fan (a plug that you can pull in and out to different fan levels). Then the whole bunch leads back to the blower at the back of the furnace.
This is getting more and more complicated I think. Thanks for your help!
At the furnace, the thermostat wires are red attached to red, black attached to Y/Y2, white attached to W/W1, blue attached to green, orange attached to nothing.
I noticed that the green wire does not come from the tstat wires, it's in a separate bunch of wires of all colours. However, it's connected to the G terminal and there's another connection to the fan (a plug that you can pull in and out to different fan levels). Then the whole bunch leads back to the blower at the back of the furnace.
This is getting more and more complicated I think. Thanks for your help!
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Sorry, I forgot to ask whether there are any terminals where there are no wires attached on both the tstat and furnance ends.
Something is definitely mis-wired on purpose or on accident.
Not sure which is the case at this time.
Something is definitely mis-wired on purpose or on accident.
Not sure which is the case at this time.
