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airheatman
airheatman, HVAC Technician
Category: HVAC
Satisfied Customers: 8274
Experience:  Furnace, A/C and heat pump specialist.
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My fan Central AC hums loudly but does not spin. I changed

Customer Question

My fan for my Central AC hums loudly but does not spin. I changed the capacitor, fan motor and the contactor. I do not know what else to do, any suggestions?
Submitted: 2 years ago.
Category: HVAC
Expert:  airheatman replied 2 years ago.
Hello. My name is ***** ***** I'll do my best to help. Let's get started and see what we can do.Do you have a volt meter to verify that you are getting proper voltage to motor?
Customer: replied 2 years ago.
No I do not
Expert:  airheatman replied 2 years ago.
My first step would be to verify proper voltage to motor.What is the model on the unit?
Customer: replied 2 years ago.
i will check my email and get back to you
Expert:  airheatman replied 2 years ago.
If you want to troubleshoot and can obtain a meter, give me model on unit and I will be glad toguide in troubleshooting
Customer: replied 2 years ago.
K55HXHEB-8584 Emerson ICP Heil Tempstar Sears 1/4 HP 230v Condenser FAN MOTOR
Expert:  airheatman replied 2 years ago.
OK lets see if we have 230 v coming out of contactors once you obtain meter.WE will gofrom there.
Customer: replied 2 years ago.
Is around 5 pm tomorrow good?
Expert:  airheatman replied 2 years ago.
I am in and out as I own a local hvac company, but hopefully will be in office then
Customer: replied 2 years ago.
I have the meter and want to try to find out the problem.
Expert:  airheatman replied 2 years ago.
Ok locate the contactors and with thermostat calling for ac check the power wires coming into the contactors, 24 volts to the contactor coil and voltage coming out of contactors;
http://i.imgur.com/3Ejsatf.png
Customer: replied 2 years ago.
I took me a little while to figure out how to use the analog meter. The voltage was 240v, 24v and 240v. Whats next?
Expert:  airheatman replied 2 years ago.
OK if we have power coming out of the contactor, although you may have just installed both, either the fan is bad or the capacitor is bad. Does the meter you got check capacitance? If so turn power off, remove wires from capaciotr ad read microfarads between terminals on cap. Must be within 3% or rating marked on cap.
Customer: replied 2 years ago.
No I have a cheap meter. I switched the old capacitor back. It is only 1 year old and looks fine. Same thing, it just hums. Brown goes to FAN red goes to C and blue goes to HERM right?
Expert:  airheatman replied 2 years ago.
Your fan wires will go to the contactors directly or one will go to contactor and other one to COM on cap.(Same terminal that is coming from cont to COM.
The only wire to cap will be brown and it goes to FAN terminal.
Expert:  airheatman replied 2 years ago.
If you could attach a photo of contactors and fan wires would be great.If you have a paper clip icon on your page you can attach using that link.Or
You can upload the pictures using the tiny pic site .
Here is a link to the site.
http://tinypic.com/
Click on Browse , select the file from your folder.then click UPLOAD NOW.
They will give you a quote to enter in the box to verify you are a human.Enter the quote and click UPLOAD NOW
You will see your picture on right side of screen.
Then copy the link URL for email & IM
Paste that link here on the site.
Customer: replied 2 years ago.
No time to send you a photo now. I took pictures on my phone but can not send them directly. I will do the picture run around tomorrow. Otherwise, I am going to put on new connections on all the wires (changed 5 so far). Thanks for the help!
Expert:  airheatman replied 2 years ago.
OK How may wires and what color are coming from the fan. I show 3 on one site and 4 on another site for same fan.Also model on the outdoor ac itself will help
Customer: replied 2 years ago.
There are four fan wires brown, blue, red and black. I can not find any model number on the Comfortmaker. Where should I look?
Expert:  airheatman replied 2 years ago.
THere should be a label somewhere on the unit giving us the model.
This is appears to be a 2 speed motor.
Customer: replied 2 years ago.
There is a paper label inside the control panel but most of the numbers are gone.
Expert:  airheatman replied 2 years ago.
Can you attach the photo ?
Customer: replied 2 years ago.
http://tinypic.com/r/2wcgz7p/8
Expert:  airheatman replied 2 years ago.
Ok I see there is a plastic molex connector on new motor, Did you not have one on old motor? If not where did the wires from old motor go to?
Customer: replied 2 years ago.
http://tinypic.com/r/eq1eub/8 is another photo. The new fan motor has the same molex connector. The wires are the same.
Expert:  airheatman replied 2 years ago.
OK they should plug in same. I am going to have to opt out as I have to leave .I have opted out of the question to see if perhaps other experts may have more information and can assist.Please do not rate or reply as that will send question back to my desk.Please stand by to see if another expert can assist further.
Expert:  airheatman replied 2 years ago.
The brown ultimately ends up at the FAN terminal of capacitor. The blue is common power from contactor (Same side of contactor that goes to COM on capacitor)and the black and red are speed wires and should connect to the defrost board
Customer: replied 2 years ago.
I still have no clue what is wrong. I tried switching the wires to the capacitor. I had thought red went to C and blue went to HERM. I switched them and the fan motor still hums just the same.
Expert:  airheatman replied 2 years ago.
OK you may have burned motor up if you wired it wrong.
Fan wires never go to HERM HERM is for the Hermetic Compressor.
And RED does not go to Capacitor.
On your motor, Brown goes to FAN on capacitor, Blue goes to either COM on capacitor or the terminal on contactor that supplies COM on capacitor , red and black are speed wires and go to the relay on the board.
Customer: replied 2 years ago.
The humming I hear is the compressor. I hooked up the blue wire to Herm on the capacitor. Are you telling me that I burnt out the fan this way?
Customer: replied 2 years ago.
I always had brown going to FAN on the capacitor.
Expert:  airheatman replied 2 years ago.
Hooking blue to HERM could have burned up fan.
Blue is COMMON power wire .It should hook to either COM on cap or the terminal on contactor that supplies power to COM on cap.
REd and Black are speed wires and neither should connect to cap. IF you connected red to COM could also burn up fan.You said "I had thought red went to C and blue went to HERM" Connecting either of those that way could burn up motor.
Lets do this.
Connect Black to one side of contactor, Blue to other side of contactor, make sure there is a common wire from contactor to Com on capacitor(Same terminal as blue
) , and connect brown to fan on cap . (This is for a test to see if motor is burned up or still good.
Expert:  airheatman replied 2 years ago.
Re read post above as I had a typo. In this test do not connect red to anything. Blue to cont or com, black to other side of contactor and brown to fan on cap
Customer: replied 2 years ago.
I do not understand. Do you want me to take the red wire of the capacitor that goes HERM and try to turn it on?
Expert:  airheatman replied 2 years ago.
Tell me if this looks like the little defrost board and if you see terminals HIGH and LOW on your board?
http://i.imgur.com/orSyevs.png
Customer: replied 2 years ago.
Something close to that, yes? It says thermostat on it.
Expert:  airheatman replied 2 years ago.
Connect Brown to FAN on CAP
Connect Blue to COM on capacitor
Connect REd to LOW on board
Connect Black to HIGH on board.
Customer: replied 2 years ago.
I think you are talking about the fan motor wires? They are in a plastic molex connection.
Expert:  airheatman replied 2 years ago.
Yes the fan motor wires. AS they come out of the connector, this is where they should go.
How have you been moving them around to the places you mentioned?
Customer: replied 2 years ago.
I had the wires hooked up right. Not moving anything around. Thought you wanted blue to go to C, but you wrote COM. I switched them back the right way in a second.
Expert:  airheatman replied 2 years ago.
I am confused. You sated the following:
Brown goes to FAN red goes to C and blue goes to HERM right?
I tried switching the wires to the capacitor. I had thought red went to C and blue went to HERM
I hooked up the blue wire to Herm on the capacitor.
I am not understanding how you connected these wires as stated since they all go to the connector.
Expert:  airheatman replied 2 years ago.
I am going to opt out as I have to leave office. Will check in to see if you have been helped when I return.I have opted out of the question to see if perhaps other experts may have more information and can assist.Please do not rate or reply as that will send question back to my desk.Please stand by to see if another expert can assist further.
Expert:  airheatman replied 2 years ago.
I am back PLease explain:
I am confused. You stated the following:
Brown goes to FAN red goes to C and blue goes to HERM right?
I tried switching the wires to the capacitor. I had thought red went to C and blue went to HERM
I hooked up the blue wire to Herm on the capacitor.
I am not understanding how you connected these wires as stated since they all go to the connector.
Below is a wiring diagram that may help you. Since you can not give me model on unitI am sending a Comfortmaker diagram, may vary a little but should be pretty accurate especially the fan wiring.
http://i.imgur.com/Y5gQ3T4.png
Customer: replied 2 years ago.
I have it hooked up right. I am biting the bullet and going to hire someone to fix it. I have almost always been able to fix just about anything myself so I am suprised that I failed. You guys were great helping me and thanks for your patience. I will let you know what was wrong so you can also have closure!
Expert:  airheatman replied 2 years ago.
Please let me know the outcome.Thanks for letting me work with you.If my answer has been polite, professional,and thorough, please click one of the ratings now. If you still need help let me know!.Expert is not paid for assisting you until you rate answer.Feel free to follow up for 30 days at no additional cost.
Leaving a poor service rating will not automatically refund your money,but reflects poorly on your expert. You have to request a refund if not satisfied with the information provided being accurate.