Central air fan not running
Posted 02 August 2006 - 11:12 AM
I came home and the central air unit outside was buzzing but that was it. No fan, nothing. I shut it off and waited about an hour to start it up. This time it sounded like the compressor was trying to run, but the fan wouldn't. I gave the fan a nudge to see if it was binding, but it ran freely and actually started to run.
Although the fan didnt seem to run at 100%(maybe 75% normal speed) cold air was again flowing through my house........for about 10 minutes.
The fan on the central unit stopped and would not go even if I prodded it a little. The compressor was still making a noise like it was trying to work, and parts of the unit were extremely hot.
I have read similar posts, but I would more than appreciate any insight as to what is actually going wrong and what I would have to replace. I am a jack of all trades, and master of none and dont mind jumping into a project I know nothing about as long as I have some good advice leading me along the right path.
And brothers and sisters, I'm at the bottom end of the learning curve when it comes to central air. Thanks.
Posted 02 August 2006 - 05:12 PM
The compressor has an internal limit which protects it if it gets too hot. When the fan stalls the compressor overheats and stops. Applianceman had a post a while back about getting the fan blade off the motor. It's not a hard job if you can get the right motor.
Posted 04 August 2006 - 11:11 AM
On the old motor there were 3 wires, yellow, black and brown. On the new motor, I have yellow, black, brown and brown/white. I was told to hook up the brown and brown/white to the new capacitor and then just connect the Y and Bl to the old connections.....but.....
When I looked at the old connections it went like this. Yellow was connected to the main power switch while the brown and black were connected to the capacitor. On the black connection side of the capacitor there is a black jumper cable leading to the power switch opposite the yellow. Soooo, if I hook up the new motor and connect Br and Br/wh to the new capacitor, Y to the Y, I still have the black that I'm really not sure where it should go.
Should this also be connected to the capacitor? along with the original black jumper? If you can decipher this mess, I would be grateful.
Sitting here sweating my Ace off.......
Posted 05 August 2006 - 01:09 AM
Posted 05 August 2006 - 07:05 AM
U don't have extra wires:) Ur new mtr is just wired differently then the old one. The yellow and black are the power wires and the brown-brn/white go to ur capacitor.
Turn Power off !!!!:poison:
With UR old mtr the black wire went to a power source (L1). Connect the black wire of the new mtr to this connection. Now on the old mtr yellow and brown went to the capacitor. Yellow(most likely) went to the terminal of the cap with another power wire on it (L2), and brown was on the other capacitor terminal all by itself.
What U have to do now is hook the yellow of the new mtr to the wire that was on UR old capacitor with the old mtr yellow wire(L2). Just splice them together. They do not go on the capacitor any more. U should now have UR blk wire connected to a power wire, and the yellow should be connected to its own power wire. . The brown wire goes to one terminal of UR new cap and the brn/white goes to the other terminal of UR new cap
Hope this helps:)
Posted 05 August 2006 - 07:07 AM
Posted 05 August 2006 - 07:11 AM
Posted 05 August 2006 - 07:17 AM
Posted 05 August 2006 - 07:34 AM
Thats leaves black and yellow(the power wires)
turn power off:poison:
I think in UR post U said yellow went to a switch? Most likly U meant the contactor:) Connect the yellow lead of ur new mtr to this same connection(L1). That just leaves the black wire.
On the old mtr U said the black wire went to the cap and there was a jumper wire on the cap with it. That jumper wire is (L2). Another power wire. Splice the blk of the new mtr to this jumper wire. Your fan mtr should now turn when U re-apply power and make a call 4 cooling.
Do U have a volt meter??? U can make this check before hooking any thing up, but it has to be done with power on so BBBB very carefull.
If U touch 1 test lead up to where yellow was connected to and touch the other test lead up to the black jumper you should read 208-230VAC. If U do then hook the mtr up as I perscribed
Get back to me :)
Posted 05 August 2006 - 07:41 AM
Posted 05 August 2006 - 07:48 AM
Posted 05 August 2006 - 08:04 AM
Posted 05 August 2006 - 08:13 AM
Yeah thats what it sounds like. U have 2 main power wires coming into the unit from the disconnect switch or circuit breaker. With power on to the unit but the thermostat off check the voltage on these 2 wires.
Again it should be 208-230VAC. If its not then the prob is ouside the unit, most likey a blown fuse. If it is then we need to dig deeper. Let me know
PS. If U'd like U can send me a private message by clicking on my handle, instead of having to post all the time.
Posted 05 August 2006 - 08:16 AM
Posted 05 August 2006 - 08:19 AM
Posted 05 August 2006 - 08:55 AM
Question though, first thing i did was check the fuses and they were fine.......did I do something while changing the fan motor to blow the fuses?
Cooling off with an ice cold beer in my soon to be cooled off home....;)
Posted 06 August 2006 - 11:13 AM
;) Thanks 4 the kind words. U and the family are most welcome. I think I need 2 open up my own school. I love teaching this stuff. HVACR is the best field (IMHO:)).
I get 2 work with my hands & my head, and its been very, very, good 2 me.
Its possible that 1 of the mtr hook ups could have taken out the fuse. The best way to check a fuse is with continuity ( no power and the fuse in your hand:))
Enjoy the rest of the summer !!
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