Furnace Motor Trips Breaker

I can't figure this out. I have a radiator in my furnace plenum. I am trying to use an hold Honeywell Fan limit switch to tell the motor to turn on when the radiator is hot.

The problem is whenever I put power to the fan I trip the fuse. I have the white/common wire going to the capacitor. The hot wire going to the yellow fan wire, and ground to furnace body. I can't figure out why it's doing this. I have the fan motor isolated from the rest of the electronics in the furnace. Please help

No idea other than to first ask if you are perhaps mixing 24 VAC and 120 VAC?

Can you explain the 3 wires on a two prong outlet? What is the amp rating on the motor you are trying to start? Shouldn't black be to black?

skobydog wrote:The problem is whenever I put power to the fan I trip the fuse. I have the white/common wire going to the capacitor. The hot wire going to the yellow fan wire, and ground to furnace body. I can't figure out why it's doing this. I have the fan motor isolated from the rest of the electronics in the furnace. Please help

If the drawing is correct for that motor, it looks like you are hooked up right. You should be able to connect the hot (black), to the yellow, red, blue or black wires to select the speed.

The body of the fan motor should have a wiring diagram on it. Does that match this drawing?

-Don

Fuse or breaker? How much current does the motor require at start up and what is the breaker or fuse rated at, and if its a fuse should it be a slow blow..

I am trying to use an hold Honeywell Fan limit switch to tell the motor to turn on when the radiator is hot.

Just how are you doing this ?

The problem is whenever I put power to the fan I trip the fuse

How are you doing this also? with or with out the above switch.. if you were to plug the motor into an outlet would it trip, is this what your doing ?

It's working now. I removed the second white wire. It's strange because it seems like it just feeds back to a common wire that is on the same circuit as the outlet I'm using to power the fan motor.

Not sure but what should have taken 20 mins ended taking me all day.
I don't know if it's because this wire was connected. The schematic says the wires are joined together exiting burner. It doesn't make sense to me but when I removed that common white wire from the capacitor it now works. Maybe the plug I'm using has a short?

By chance is this circuit a GFI ?

grumpy wrote:By chance is this circuit a GFI ?

No GFI. Since I removed the second common wire from the capacitor it now works. I should have tried that earlier.

Hum.. maybe is was tied to line...

It's possible that the starting capacitor is bad, and now it's out of the circuit.

-Don

StokerDon wrote:It's possible that the starting capacitor is bad, and now it's out of the circuit.

-Don

I was thinking that too, but he only removed one wire..