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Phil
Phil, Mechanical Engineer
Category: HVAC
Satisfied Customers: 6022
Experience:  Retired HVAC/ Electrical & Boiler contractor. Industrial
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I just installed a new motor

Customer Question

I just installed a new motor for my central air system. I installed a new one in my other system a few days ago, and copied my wiring exactly as I was instructed to do in the last one, but this time the fan is not turning on when I start the system. Can you please look at this photo and help me with the wiring?
Submitted: 2 years ago.
Category: HVAC
Expert:  BillyHvac replied 2 years ago.
hello,
can you list wire color and terminals or post a pic?
Customer: replied 2 years ago.
Wire colors on the new fan are: white, black, brown, brown/white, green, purple, yellow.
All wires are connected as you can see in the link to the photo below, and the brown/white wire was capped off.
Here is a link to my photo:
http://postimg.org/image/pd5toaozl/
Expert:  BillyHvac replied 2 years ago.
Ok first...confirm this is the condenser fan motor in the top of the ac unit?
And the compressor runs but not the fan?
Customer: replied 2 years ago.
Yes, the fan motor hangs from the top of the unit, and the condensor turns on when I press the button in the middle of all the power wires, but the fan doesnt turn on.
Expert:  BillyHvac replied 2 years ago.
Ok,
I see the old capacitor is still in place.
This capacitor can be bad on the fan side...and also it may not match the microfarads of the new motor. On the side of the motor..or the box...will be a cap rating needed. It will appear as (example) 7.5uf.
1 - if the capacitor is bad on the fan side it will not work
2- the cap should be changed whenever changing a motor to the cap value.
Try this....if you pressin contactor....and manually spin the fan blade...does it stop right away or try to start ?
Expert:  BillyHvac replied 2 years ago.
And I see a wire is missing from cap to contactor....what is model of the outdoor ac?
Customer: replied 2 years ago.
The capacitor is not bad. I tested it in the other central AC that is exactly the same as this one 2 days ago and it worked perfectly.
I just tried pressing the contactor and manually spinning the fan, it doesnt stop right away, just keeps spinning but doesn't feel like there is power going to it
Customer: replied 2 years ago.
It's a Rheen RAKA 024JAZ. I am not sure which wire is missing as I have it wired exactly as the other one next to it and that one is running fine.
Expert:  BillyHvac replied 2 years ago.
Ok,
but does the microfarad rating on the old cap match the NEW motor...I am pulling schem...and what model motor then I will have all in front of me.
The cap rating is important vs motor used...
Customer: replied 2 years ago.
I am not sure which rating the capacitor has, but the new motor matches the specs from my old motor, exactly, and it's the same motor that is working in the other AC with the same capacitor (I replaced both motors).
Expert:  BillyHvac replied 2 years ago.
Please be patient as the wiring is not the same as the original diagram shows.
The diagram shows 4 wires to the capacitor. One on Herm (compressor purple)
one on fan (brown) and 2 on C...an orange wire to the contactor opposite black
and a orange from fan motor...
on your unit next to it...are there only 3 wires to cap?...as I do not see how it can complete line 2 circuit without going to contactor
Customer: replied 2 years ago.
Yes there are 3 wires going to the capacitor... My other AC has the exact same wiring and it's running as it should. Here is a link to a photo of my AC that is wired and working, exact same AC model, motor and capacitor, but there is a white wire where there is a red wire in my other AC. http://postimg.org/image/fvecd5zpv/
Expert:  BillyHvac replied 2 years ago.
well,
last thing I need...is motor model..I know by looks it appears the same.
But it is not matching my drawing...
I am going to copy what I have an post...just a moment as I have to use a file share site
Customer: replied 2 years ago.
This is the new motor I am using in both my AC's, here is a link. The guys at the supply house said the motor will work with my model and my capacitors. I believe this is a wiring issue. http://www.amazon.com/gp/product/B007VJKPLC?psc=1&redirect=true&ref_=oh_aui_detailpage_o03_s00
Expert:  BillyHvac replied 2 years ago.
Looking at your motor now..
here is wiring I show
https://www.mediafire.com/?oyoxcaa3whdhu78
Customer: replied 2 years ago.
This doesn't make sense to me ? That is why I asked for expert help
Expert:  BillyHvac replied 2 years ago.
I have schematics that do not agree...so the very easiest thing is to do the following.
This motor is made to use its own capacitor..thus the 2 browns.
Go to supplier, get capacitor for the motor..it will have just 2 sets of prongs not 3.
Put brown on one side and brn/wh on the other and leave black and white where they are.
That is it...it is harder to wire these with a dual cap suach as yours. While there you may want to get a contactor or 2 as in the pic your contact points are shot...
so very basic...new cap for $10....use the 2 browns to cap...black and white to contactor and your done.
reagardless of schematic...that is how the new motor is designed.
Customer: replied 2 years ago.
I would like to wire these without having to replace the capacitor. I tested voltage on the capacitor and I am getting 24. The same capacitor is working in my other unit but I am missing something and I want to get it to work without replacing the capacitor like with my other AC.
Right now I have the brown/white wire taped off because another expert said I don't need it with this capacitor?
Expert:  BillyHvac replied 2 years ago.
Well we are at an impasse because for some reason you do not want to change the capacitor.
BUT - EVERY TIME you change a motor or compressor you are to replace the capacitor. It is NOT voltage we measure. It is microfarads. And if do not replace the capacitor it voids warranty.
So whether you stay with 3 set terminal on the cap...or put in a 2 terminal for the fan..it should be done. And you still not have confirmed that the microfarad rating matches the new motor.
Once again...on a cap voltage is NOT our concern. And even if the microfarads were matching...you still (always) replace the capacitor with the motor. Its a good way to lose another motor by leaving old capacitor in.
I am going to opt out and give someone a chance to evaluate your concern...but if I were on site....I would change to a matching new capacitor...and new contactors as yours is in very poor condition at the contact points and can cause these failures also.
Please remeber that not changing your capacitors when replcing motor or compressor can lead to catastrophic failure of the expensive parts...and a capacitor is cheap.
I wish you well on your repair and will open to the others.
Customer: replied 2 years ago.
It's not that I don't want to change it, it's that I live in a rural area, and it's not easy for me to go drive 50 miles to change a tiny part. I have explained to you that another expert told me that I do not need another capacitor, the problem is that you weren't able to answer my question which was to help me wire it with the current capacitor. Instead you send me diagrams which had nothing to do with my question.
Expert:  Phil replied 2 years ago.
Welcome to 2 hours help.

Up to 48 hours trouble shooting and coaching on repairs $38 additional if you approve it at that time.
.
You can order the capacitor on line and have it mailed to you, those sell for $7 or so.
There is generally a sticker on the side of the new motor, any motor with a brown and brown/white wire connected to it requires a capacitor... the advice you got that says none is required is incorrect.
Take a look at Billy, recent response, he runs the service department of a large HVAC contractor for decades now. He is one of our highest rated, and most prolific consultants here.
The name plate on the motor should tell what micro farad rated capacitor is required.
If you can attach a picture of the wiring diagram sticker on the side of the motor I can show you how to wire it.... I also need a close up, well focused, well lit picture of the wiring diagram glued to inside of the blower service panel, taken straight on so that I can read the text on it when blown up. I mark those up with wiring instructions.
Use the 'attach files' link at the bottom left of your reply box to attach the picture.
We can go from there.
.
Customer: replied 2 years ago.
I was absolutely not questioning Billy 's qualifiations and I appreciate the help, but the issue I have explained several times to him is that I have a second unit, the same model, motor and capacitor and another tech was able to help explain to me how to wire that motor to the existing capacitor. All I trying to do is to do the same exact thing with my out of service AC as I did with the other one several days ago. I did not need a new capacitor, the existing one worked and I was able to have it wired to the new motor with no issues.
Customer: replied 2 years ago.
Here is a photo of how I have wired it, but it's not working with this wiring, just the condenser turns on, not the fan.
Expert:  Phil replied 2 years ago.
Hello again,
That picture of the contactor needs to show Line and Line 2 coming in with a green ground, and terminal 1 and terminal 2 going out to BOTH the compressor and fan motor.. there are no terminal 1 and terminal 2 wires connected at all that run to the fan motor.... unless they are on a separate terminal block not show in the photo,
and... that capacitor shown (I can't tell for sure if its a capacitor but it is wired like a *dual* capacitor that runs both the compressor and the fan motor. not a single capacitor as the two brown wires would normally go to.
--------------
if the blower motor capacitor had only two cup terminals on it, run each of the two browns to separate cups on the capacitor.
Then check the motor amperage to be sure it does not draw more than the rated amperage, if it draws more than the rated amps when connected for high speed, the capacitor is the wrong micro farad rating, and will run the motor, but will cause it over heat and burn out, sooner or later, depending on how far out of range the old capacitor is.
Can you copy the wiring on the in-service unit? Is it the same brand and model number motor?
If not I need the photo's I mentioned earlier.
We can go from there.
.
Customer: replied 2 years ago.
Hi Phil, Yes, it is a dual capacitor, that is what the other tech told me. Attached is a photo of the AC that is in service, it's wired exactly as the other tech told me to a few days ago, I tried copying the wiring with this other AC and it's not turning the fan on so I believe something is amiss but maybe you can see something in the photo that I am missing?
Expert:  Phil replied 2 years ago.
Hello again,
http://screencast.com/t/MHkZQQj05cm
.
Customer: replied 2 years ago.
Phil, I am not sure what the photo was trying to show me, but I am going to go get a new capacitor this morning. The fan reads: 5 MFD 370VAC so I am assuming that is the capacitor I need? The old capacitor that you said might be bad says: 30.0 3.0 370 VAC
Expert:  Phil replied 2 years ago.
Hello again,
Please do not buy anything just yet, things can get progressively messier that way and burn off the time we have to get the situation resolved without going into over time.
I *need the photo of the wiring diagram to continue effectively... taken close up, well lit, well focused, and from straight on.
.
Customer: replied 2 years ago.
Hi Phil,
I bought the new capacitor that matched the required specs according to the fan motor. The new capacitor is doing the same as the previous one.
Expert:  Phil replied 2 years ago.
Hello again, there is most likely a wiring error, or a defect somewhere else in the system that I will not be able to coach you on without a photo of the wiring diagram.
I will opt out and we can see if any other of our experts here want to tackle this sans diagram, and with probable wiring errors etc.
Good luck with it.
.
Customer: replied 2 years ago.
Can a moderator please just close this question? I am asking the previous tech who helped me inside another thread. I can't believe these 2 techs sent me to buy a new capacitor without even diagnosing the issue first.

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