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Phil
Phil, Mechanical Engineer
Category: HVAC
Satisfied Customers: 5648
Experience:  Retired HVAC/ Electrical & Boiler contractor. Industrial
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Billy I'm ***** ***** - my heat/Air unit is humming and no

Customer Question

Customer: Hi Billy I'm ***** ***** - my heat/Air unit is humming and no air is coming thru the vent even though the fan is running out side. This is an inside unit...
JA: Thanks. Can you give me any more details about your issue?
Customer: I'm not sure how to reset it and what other detail would you like.
JA: OK got it. Last thing — HVAC Technicians generally expect a deposit of about $18 to help with your type of question (you only pay if satisfied). Now I'm going to take you to a page to place a secure deposit with JustAnswer. Don't worry, this chat is saved. After that, we will finish helping you.
Submitted: 10 months ago.
Category: HVAC
Expert:  HVAC Guru replied 10 months ago.

Hello and thanks for using this service, if you have been waiting do not worry or get upset I am just one of the techs on here and I try to get to as many customers as I can and I just picked up your question now. Please give me time to respond sometimes I get your replies late so there may be a delay in my response.

If the fan is running the A coil may be iced up can you check that?

Customer: replied 10 months ago.
I live in Florida? where is the A coil at?
Customer: replied 10 months ago.
HVAC Guru Are you here?
Expert:  HVAC Guru replied 10 months ago.

In the furnace plenum or airhandler it is the coil that coils and heats.....it may be iced over

Customer: replied 10 months ago.
This unit is just humming, the fan is running out side and not air (hot or cold) is coming thru the vents.
Expert:  HVAC Guru replied 10 months ago.

OK well then the airhandler is not running, that could be a lot of things, can you get at the airhandler unit to see if any error codes are flashing on the board?

Customer: replied 10 months ago.
Where can I find the airhandler unit (make believe am a novice).
Customer: replied 10 months ago.
The unit is humming again and the thermostat is off.
Expert:  airheatman replied 10 months ago.

Can you locate your indoor unit for me and tell me if it is a gas furnace or an electric air handler? If electric there should be a label on front listing model number.get me that number and we will go from there.

Customer: replied 10 months ago.
Model # ***** Fan Coil Unit
Expert:  airheatman replied 10 months ago.

Excellent.Thanks for that information.Let me see if I have a manual so I can help with accurate information.I do not want to throw out a guess or just tell you it could be many things.I want to help you find the problem.

Customer: replied 10 months ago.
Thank you... It's an electric unit.
Expert:  airheatman replied 10 months ago.

While I am looking for a manual. there should be 2 panels on front. One will be where the cooling coil is (you will see the copper lines ). The other,usually top is where blower is. Our first step is to open that top panel and turn thermostat to heat or coil and see if the indoor blower runs.Also see if there is any ice on the copper pipes or coil.

Expert:  airheatman replied 10 months ago.

This top panel

Expert:  airheatman replied 10 months ago.

Once you have top panel removed and thermostat on, be careful not to stick your hand in blower, but take a flashlight and look in and tell me if the blower wheel is turning.

Customer: replied 10 months ago.
No - the blower wheel is not turning and the unit is humming.
Expert:  airheatman replied 10 months ago.

OK. Next let me know if you have a multi meter for troubleshooting?

Customer: replied 10 months ago.
Ok - let me get it.
Expert:  airheatman replied 10 months ago.

I am suspecting we either have a bad fan motor or a bad capacitor, but throwing out a guess without troubleshooting properly would be less than professional and not much of an expert.. With unit calling for heat or cool we want to check between FAN COM and FAN SPEED terminals on the air handler control board to see if motor is getting 230 volts.See drawing below

Customer: replied 10 months ago.
Ok - I have the multi meter - can you help me follow your diagram.
Expert:  airheatman replied 10 months ago.

Absolutely.Let me know if you see the control board and the terminals marked FAN COM and FAN SPEED. That is where we want to check for voltage.

Customer: replied 10 months ago.
my husband says he sees both of them
Expert:  airheatman replied 10 months ago.

Remind him we are working with high voltage, then with thermostat calling for cool or heat check between those terminals by putting one lead on each and meter set to AC Voltage lowest scale above 240 (Probably will be 600V on meter)

Customer: replied 10 months ago.
meter only takes 400v
Expert:  airheatman replied 10 months ago.

Excellent set to 400v and check for 230 to 240 between FAN COM and FAN SPEED

Customer: replied 10 months ago.
Do I need to pull the wire out to test or should I stick the tester in the wires? Difficulty reaching... Also could it be the fuse?
Expert:  airheatman replied 10 months ago.

1. You can pull wires out of you want. Remember to turn power off first and when wires can not touch metal, turn back on and check between wires (not terminals on board).

2. Lets's check this first.Fuse is a possibility but not as likely since you have a hummimg.

Customer: replied 10 months ago.
Ok - I change the fuse and it good. When I tested the wires I only got 2.8 reading.
Expert:  airheatman replied 10 months ago.

LOL. My bad. I told you to check wires, We need to check terminals since wires are unplugged.

Customer: replied 10 months ago.
No - I'm not get 230v or anything close to it.
Customer: replied 10 months ago.
No - I'm not getting anything close to 230v
Expert:  airheatman replied 10 months ago.

What are e getting? Also check from each of those terminals to ground on cabinet

Customer: replied 10 months ago.
I thought we weren't going to touch any metal?
Expert:  airheatman replied 10 months ago.

Do not let wires touch metal when they have voltage on them. We are going to put a meter lead to metal ground and a meter lead to each of the FAN SPEED and FAN COM to see what we have on each leg.

Customer: replied 10 months ago.
Ok - this is with the power off - correct.
Expert:  airheatman replied 10 months ago.

No power on and calling for heat every time

Customer: replied 10 months ago.
FANCOM = 194 COMSPEED=44.5
Customer: replied 10 months ago.
FAN COM= 194.3 FAN SPEED = 44.5
Expert:  airheatman replied 10 months ago.

Something mot jiving there. The two terminals receive power from the two legs of a 230v double pole breaker.Are you sure meter is set correctly and good batteries? We should not be getting more than about 125 volts max from one leg od the breaker.(One terminal)

Customer: replied 10 months ago.
That is correct!
Expert:  airheatman replied 10 months ago.

If meter is set correctly and good batteries lets do same thing at the actual breaker that supplies voltage to air handler.(In main power panel)

Customer: replied 10 months ago.
I did not put a multi meter on it , I put an electric tester on it and it was live. The bulb lit up.
Expert:  airheatman replied 10 months ago.

I am not understanding . Where did you get the 194 and 44.5?

Customer: replied 10 months ago.
From the multi meter testing
Customer: replied 10 months ago.
The main box reads 244.2 (multi-meter reading)
Expert:  airheatman replied 10 months ago.

I am still confused. You said you put the multi meter on those terminals and then you said you did not put a muli meter on it but used a meter with a bulb.Help me understand.

Expert:  airheatman replied 10 months ago.

Excellent now at breaker the 244 is good. Lets go each leg to ground in panel

Customer: replied 10 months ago.
I used the multi meter for all testing except when I first test the main box. When I first tested the main box I used a regular electric tester to find out if there was any juice in it. Then I used the multi meter and got a reading of 244.2
Customer: replied 10 months ago.
I got 120.5 and 122.4
Expert:  airheatman replied 10 months ago.

Excellent.Thanks for clearing that up. Now lets go back to air hander and locate the power wires coming into unit and do same. Check between them and then each leg to ground.

Customer: replied 10 months ago.
coming from the unit. between them 257. each leg to ground 230 & 240
Customer: replied 10 months ago.
Turned on unit again still humming & clicking but the fan is not spinning
Expert:  airheatman replied 10 months ago.

Not making good sense on our power. If we have 120.5 from a leg of breaker to ground at breaker, We should have that same 120.5 at unit on that leg

Customer: replied 10 months ago.
the power was fluctuating or jumping.
Expert:  airheatman replied 10 months ago.

We should have steady power pretty much, maybe fluxuating a few volts, but no way we should have 230v to ground from a breaker that is sending 120.5 to ground.Wondering if there is an issue with meter.

Customer: replied 10 months ago.
I'm not getting enough juice from the electric tester to light the bulb. The area where I'm testing has the yellow com and three different com speeds (low, med and hi) the yellow is in the com and the black was in low - I'm I in the right area?
Expert:  airheatman replied 10 months ago.

Get rid of the light tester. If will not work for what we are doing.We want to be at the very first lugs where power comes to furnace and using the meter right now. Can you send pictures showing what you are doing?

Customer: replied 10 months ago.
Having hard time sending pictures
Expert:  airheatman replied 10 months ago.

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 10 months ago.
My pictures are not down load correctly tonight - is there another way.
Expert:  airheatman replied 10 months ago.

I am about to have to leave so I am going to open this to other experts so you do not have to wait.

Customer: replied 10 months ago.
Thank you and thank you for your help!
Expert:  Tim H. replied 10 months ago.

Hi, I'm Tim and I'm an HVAC expert here to help answer your question(s). Please provide all the information I ask for since I'm not onsite. At the end of our dialog you will be asked to rate my service, but please wait until then and all your question(s) have been answered satisfactorily. If you are not satisfied, I'd appreciate it if you'd tell me why before leaving a negative rating and allow me to continue to work with you until we are able to both agree on an outcome to follow. Thanks for your business!

You say the indoor unit is "humming". Can you open up blower panel, find the blower wheel, and try to spin it with power off. Let me know what you find.

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