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Air dish troubleshoot? #158618 07/16/06 04:27 AM
Joined: Apr 2004
Posts: 79
Steve McKinney Offline OP
Hey fellas,

It is 3:00 in the morning and it is too hot in my house to sleep. My a/c went out yesterday afternoon(that's Saturday afternoon, thank you very much) and I am up on the "net" to see if I can trouble-shoot my a/c unit. Hey, electricians can fix anything, right?

My question to you guys is this............are any of you set up or just do a/c trouble-shooting as well. I'm not looking to become a full fledged "tin bender", just wanting to be able to have another service to offer. Is it worth it?



Business, Office, Estimating, Legal:
Re: Air dish troubleshoot? #158619 07/16/06 09:28 AM
Joined: Jan 2004
Posts: 105
chi spark Offline
Steve, what are the symptoms of your a/c problem? Following basic safety rules, there is a fair amount of troubleshooting that an electrical tech can do. Refrigeration units were originially sold and serviced by electrical contractors back in the day...
is it central a/c?
if so, is the outside unit running?
is the condenser clean?
is the inside air filter clean?
is the inside unit fan running?
is the outside unit fan running?
is the outside unit compressor running?
is there power present to outside unit?
is there control 24v to outside unit?
is the contactor for the outside unit making?
if it is a window unit, there's a bit more of control/cleaning/disassembly issues.
if it is central, most common problem- dirty condenser-in northern IL, our cottonwood trees can plug it up bad. Have you ever cleaned the condenser?

Re: Air dish troubleshoot? #158620 07/16/06 10:35 AM
Joined: Jan 2005
Posts: 5,316
renosteinke Offline
Cat Servant
As luck would have it, I had an AC call last night. Here's what I did:

Right volts coming in? Yes.
Right volts at unit? Yes
Thermostat in correct setting? Yes
Was unit running? Yes
Was hot air coming out of the fan at the condenser? No.

Diagnosis- AC is not making 'cold.' Not my trade. Call AC guy.

Re: Air dish troubleshoot? #158621 07/17/06 11:28 AM
Joined: Apr 2004
Posts: 349
Radar Offline
Steve - I think your idea is fine as long as the problems are electric. I would bet tho that most times AC problems refrigerant related. Mayne not, and certainly not all the time.

Just a couple of weeks ago my AC was acting just as Reno describes above. I grabbed my amp probe and headed for the condensing unit. Voltage was good, fuses good, but measured only 2 amps draw (for a 4 ton unit) - the condensor fan is running (duh!) but the compressor is not. This is an old Payne unit, but I had been able to salvage, scan and copy a wiring diagram when I first moved in a few years ago. And what I found was that a loose connection had fried a lug on the compressor motor overload relay in the wiring compartment. These are really strange relays.

I was able to scab on a replacement lug to get going again for the short term, and then I found a replacement at US Air, a local distributor. I'm surprised at that because of the age of this thing. Anyway, I rechecked the amps a couple of times after installing the temp fix and then the replacement relay, couldn't find any other problems.


There are 10 types of people. Those who know binary, and those who don't.
Re: Air dish troubleshoot? #158622 07/17/06 12:16 PM
Joined: Apr 2004
Posts: 79
Steve McKinney Offline OP
Thanks for the input fellas. I can see that I am not alone in wanting to tackle/solve our own problems.

Condensing unit was icing over. Best I can tell, either the central air condensing unit is not going into "Defrost" when it is suppose to or it is low on gas.

I'll keep ya posted.

Re: Air dish troubleshoot? #158623 07/18/06 10:06 AM
Joined: Apr 2004
Posts: 349
Radar Offline
Condensing unit was icing over.
I've seen the inside cooling coils ice up - is that what you're saying Steve? From what I understand this occcurs because of imporper refrigerant charge and/or insufficient air flow (which then gets worse as ice builds up).

I don't believe I've ever heard of an ice-up on the outside condensor unit, but then I'm no expert in this. I have a friend who is an AC service guy, and I'll ask him about it when I see him again.


There are 10 types of people. Those who know binary, and those who don't.
Re: Air dish troubleshoot? #158624 07/21/06 04:21 PM
Joined: Feb 2006
Posts: 138
PE&Master Offline
I don't think split a/c units have a defrost stage. Generally it's an air flow problem and you'll find your evaporator in the furnace is iced over as well.

Either the circ fan is not running when the compressor is (t-stat probably bad, control board in furnace is bad, or recirc motor has a problem) or your air filters are too dirty.

Always start from basic principles and build from there.

Re: Air dish troubleshoot? #158625 07/26/06 04:27 PM
Joined: Apr 2004
Posts: 79
Steve McKinney Offline OP
Ended up low on gas. Couldn't have "fixt" it anyway.

Found out from a co-worker that as of Jan. 1 of this year, you can not install anything less than a 13 SER unit for even residential.

Thanks for the input fellas!


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