The blower motor on my furnace/AC burned out, and I had it replaced. He replaced the motor and the capacitor. Now it doesn't work right. On heat mode with the fan set to AUTO, the blower runs for only about a minute (see next paragraph). On heat with fan set to ON, the blower doesn't seem to come on at all. When it is set to cool, the blower doesn't seem to come on at all.

Even before the blower burned out, it would only work for a short time (30 - 60 seconds) before turning off. It would do this several times during the cycle. It's been like this for years. I just kept the fan in the ON position all the time, and it worked OK.

There are three wires coming from inside my furnace, yellow, red and blue. Originally, these were all connected to the blower motor. after the replacement, the blue is no longer connected to anything. The connections are now: yellow from furnace to yellow on motor, red on furnace to black on motor, two browns on motor to the capacitor. There is also another set of wires coming from the motor that are jumpered to each other: brown to orange, yellow to purple.

My questions are: Should the blue wire from the furnace be connected to something? Could the wiring cause the fan not to work in ON position? Could the fan burning out cause something else to go bad and stop the motor while it's in the ON position?

Thanks for any help you can give.

 

Sounds like he didnt tie in the high speed to work on the fan on and with the AC.

Call him back on it now.


ED

 

I called him, but he haqsn't called back. Hopefully that's because of the Easter holiday.

Does the blue wire have anything to do with that, or would the problem be somewhere else?

 

Sounds like he screwed up. Id ask first is this the same motor as for how many speeds the Hp and the rpm of it. It turns the right way? check all that out. He dont have it wired right is what it sounds like.


ED

 

The repairman never answered any of my calls. I checked the wiring diagram, and the red and blue wires come from the indoor fan relays (there are 2). It looked like the power is routed through one or the other wire.

I connected the red and the blue wire together at the motor. (In the old motor they were separate, and after the motor replacement the blue wire was not connected to anything.) Now the fan comes on when the fan switch on the t-stat is set to ON.

Is it going to cause any problems to connect the blue and red wires? Is it going to burn up the motor or start a fire? I usually keep the fan ON, so the blower speed doesn't matter to me.

 

You connected the red & blue motor wires together? Disconnect them now. The motor you have is a 3 speed motor. Red is low speed, blue is medium, & black is high. Normally only 2 speeds are used & the third is capped off. The diagram on the furnace might tell you which furnace wire goes to which motor speed. The brown/orange & yellow/purple are to reverse the direction of rotation.

 

I don't think I explained it very well. The red and blue wires come from the Indoor Fan Relays on the control board. It looks like only one of them has power at a time. The motor only has one wire, which is black. (There are also yellow and brown wires, but these seem ok.) The original motor had a place for both the red and the blue wires (and the yellow and brown ones).

When only the red wire is connected to the black motor wire, the fan only runs if the t-stat is set to AUTO and HEAT. The fan doesn't work when the switches are set to ON or to AUTO and COOL. When both the red and blue wires are connected to the black motor wire, the fan works with any switch setting.

Should I still disconnect the red and blue wires? If so, how should I hook it up? I know the best thing would be to have the right motor, but I can't get the repairman, and I do not have another $300 to get someone else to fix it. Would it work to connect the blue wire instead of the red one, and just leave the fan set to ON?

Thanks for your help.

 

When you take off the panel to the airhandler there should be a wiring schematic glued to it. Look on there very close and you'll see a circle with the letters IBM or something of the sort, it may even be printed indoor blower motor. The lines coming out of it will show you what each color wire represents as in speed and what is the common. Also on the side of your new blower motor it will have a small diagram depicting what lead is what speed.


In your 1st post you said the Red wire was connected to the Black on the motor. Now you say you connected the Blue to the Black and the blower works fine in the "on" position? So now the Red wire from the furnace is going to nothing? "I hope".

If it's working good on the same speed and just using the furnaces "blower on" wire instead of the furnaces "heating blower on" wire. Then you have a problem with the furnaces fan relay that turns the blower on for heating mode.

Your furnace should operate with no problems like this. The only downside or danger would come to play if you forgot to turn the blower to on and tried to run the heat for an extended amount of time. It's very possible in that situation that the furnace continuously trying to run with no blower could overheat the heat xcngr.

If you run the blower in the "on" position all the time make sure you change your filters often.

 

Actually I had the red, blue and black wires were all hooked together, but I've now disconnected the red wire, and it not connected to anything. The blue wire is connected to the black wire of the motor and the fan works for all settings except for HEAT/AUTO. I'll leave it like this until I can get the right motor put in.

Thanks to everyone who answered my questions. You've been a lot of help.

 

I don't think it's your motor. I'll bet it's your relay.