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Phil
Phil, Mechanical Engineer
Category: HVAC
Satisfied Customers: 5648
Experience:  Retired HVAC/ Electrical & Boiler contractor. Industrial
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One of my ac units is not blowing cold air, air comes out

Customer Question

hi.
JA: Hi. How can we be of help?
Customer: one of my ac units is not blowing cold air
JA: Did you double-check the thermostat's settings? And what about the filters?
Customer: air comes out but not cold...the unit outside does not turn on..the fan part
JA: Do you plan on doing the work yourself?
Customer: filters are new.. new batteries....
JA: Anything else we should know to help you best?
Customer: I was going to yes
JA: OK. Got it. I'm sending you to a secure page on JustAnswer so you can place the $5 fully-refundable deposit now. While you're filling out that form, I'll tell the HVAC Technician about your situation and then connect you two.
Submitted: 5 months ago.
Category: HVAC
Expert:  Phil replied 5 months ago.

Hello, I need the brand name, model number and age of the unit outside that is not running... and I need to know how hot it has been lately.

Tell me a lot about your technical skill sets and if you have a multi meter or not so that I can coach you most effectively.

We can go from there.

Customer: replied 5 months ago.
it is in the 90's...going to be 100 today...I am pretty good at fixing things...I have just never done much electrical other than outlets..lights..etc....nevere an a/c..i have no multi meter
Customer: replied 5 months ago.
It is a Ducane....im trying to read the label it is the sun and faded
Customer: replied 5 months ago.
well the larger one which is working is a ac10b48-a
the smaller one which is not working is a ducane but the label is faded
ok my bets guess is its a ducane ac10b36-b
Customer: replied 5 months ago.
I repair old clocks..woodworking...wood turning..i can build just about anything with wood..I just have every basic electric knowledge. but am confident I could do this if I knew how
Customer: replied 5 months ago.
its about 10 years old
Expert:  Phil replied 5 months ago.

Thanks you will need to buy a $30 type, self ranging multi meter to check voltage to the outside unit that is not running and a few other things after that.

all hardware stores carry them.

Expert:  Phil replied 5 months ago.

Practice with it for a while, we can go from there

Customer: replied 5 months ago.
ok...I will go get one...also the fan and compressor do not turn on outside...but the thermostat turns the unit on and air comes out but not cold
Expert:  Phil replied 5 months ago.

the power is off to the outside unit, or it is not getting its 24volt signal to pull in the contactor that runs the fan and compressor, or the contactor is bad, or the high pressure safety cut is tripped. that in the diagram follow the wires to and press its reset button.

Then clean the condenser coil

https://www.youtube.com/watch?v=vDtT6hSpV4s

Expert:  Phil replied 5 months ago.

thats a summary, i will step you though it once you have a meter

Customer: replied 5 months ago.
one more thing before I head to store..just to clarify..i cannot find any indoor units...... just the outdoor ones
Expert:  Phil replied 5 months ago.

if its a box about 24 inches tall, 36 inches wide and 50 inches long its a packaged unit and will be connected to the house by air ducts,, there will be no inside unit

Customer: replied 5 months ago.
Hmm nothing on roof..nothing outside except the two separate ac condenser uits...only place could be my master bedroom attic
Expert:  Phil replied 5 months ago.

Thanks, ***** ***** the attic then if its not there and your house is not on a slab look under the house, or in the garage.

Customer: replied 5 months ago.
found them in the attic...do I need to do anything with these..i assume these are the heaters?
Expert:  Phil replied 5 months ago.

If there is a gas line running to them and a vent through the roof they are gas furnaces with a blower, and the cooling coil fits on the outlet end of the furnace.

If its not a gas furnace it will be an electric furnace and you will see a large disconnect switch mounted nearby.

remove the door from the blower compartment and take a well lit, close up photo of the wiring diagram from straight on and very very well focused... attach it here using the paper clip icon at the right end of your tool bar

we can go from there

Customer: replied 5 months ago.
its gas
Expert:  Phil replied 5 months ago.

thanks. send me that wiring diagram then, and a photo of there thermostat wire connections to the printed circuit card in the blower compartment and I will mark them up with trouble shooting instructions.

Customer: replied 5 months ago.
ok got the voltmeter...took fuse plug out. took cover off ..the capacitator has 3 prongs..i assume this does both the compressor and the fan.....its all rusted...I have not touched it. working on photo of in house unit
Expert:  Phil replied 5 months ago.

Hello again, if the capacitor is bad for the compressor side, the compressor will attempt to start from time to time and it will be very warm on top.

while it would not hurt to replace the capacitor at this stage, there is probably something else wrong, I suspect a burnt wire connection at the compressor, look for that

Customer: replied 5 months ago.
its a Copeland compressor. outside. I do not see any burnt wires..its has 3 going to it
Customer: replied 5 months ago.
trying to figure out how to send photos from my phone
Expert:  Phil replied 5 months ago.

Hello again, did you locate the actual spot where the 3 wires attach at the compressor, or just the 3 wires themselves.

do that

the next trace each of the 3 wires back to their source, two will to the T1 and T2 terminals on the contactor and one wire will go the run capacitor.

Measure the voltage across the two at the contactor, and between each of those and the one that attaches to the capacitor.

tell me what the reads are, we can go from there.

Customer: replied 5 months ago.
I cant see where they go into the compressor..id have to take the whole thing apart to access that they go into a small tube ..
Customer: replied 5 months ago.
ok I'm getting tired..can I work on this tomorrow..or sat..i work weds thru fri
Customer: replied 5 months ago.
not sure how this works
Expert:  Phil replied 5 months ago.

Hello again, there are no time limits or fixed schedules with me, just post and I will pick it up as soon as I can,

Expert:  Phil replied 5 months ago.

basically I want to see if the power, 230v is getting to the compressor or not, you can check that where the wires connect to the contactor that is inside where the all the controls and the run capacitor is.

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