Old Carrier central AC

Re: Old Carrier central AC

Greetings,

I'll keep the sob story short/sweet. Outa work 5 years. Life-Its-Ownself onna shoestring.

21 year-old 2-ton Carrier AC ("Round One") on a little bungalow in the midwest. AC did OK for most of the summer.

I set the thermostat for air. The little lite comes on, the blower blows. Nothing happens at the Condensing Unit. This happened some years ago and I had to repair an elec. connection, so I tested each connection (some corroded) on the CU. Checked wire nuts on the 220 v. connections. No help.

Unit has 150 psi equalized pressure. I believe this is sufficient to start the compressor. I have a little R-22.

Checked, tripped, reset the breaker. No help.

Can't really think of anyting else to focus on. Tstat seems to call for compressor. Compressor no go. Near as I can tell, it doesn't even click. Has to be an elec. failure of some sort?

If a good AC trouble-shooter could suggest some additional things to test or has some idea what the problem might be, I'd be eternally grateful. Service call is out of the question: gotta do my po' self.

Thanks, Puddin'

Reply to
Puddin' Man
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No control contactor clicking, sounds like a low voltage control circuit failure. If nothing works at the outside condenser, then the problem is either in the 24 volt control circuit or the 230 Volt power circuit. You need a multitester to check voltages. Set it on 230 volts so you don't damage it.

Most systems have the low voltage transformer in the furnace, however, some carriers had two TRs with one in the condenser. "If you don't know how to trouble-shoot those circuits in a totally safe manner, --you better get someone that knows how to help you!"

I would not have any problem locating the problem, but if you don't know how, well... . I won't try to go into detail as typing is too difficult these days. - udarrell

Reply to
udarrell

There ain't nobody.

No problem. You've already helped a bit.

I traced lo-volt red and white wires from furnace control to the CU. Wirenutted to brown and blue. Connection didn't look so good so I re-stripped/wirenutted the white. Turned it on and got a hum out of the CU. Shut it down, did purty much the same (re-strip, etc) with the red, and it's dead again.

It's just me and the dawg here. Takes near 10 seconds to get from the Tstat to the CU, so it mighta clicked (I dunno).

Didn't see any obvious problem at the connection panel in the furnace.

Other ideas much welcome.

Thanks, Puddin'

Reply to
Puddin' Man

On Sun, 11 Sep 2005 01:08:11 GMT, Puddin' Man wrote: Check the low voltage relay tp insure its pulling in and the contacts are good. Then go to the capacitor... if it's dual pole (probably) you can replace... a good indicator of the capacitor is that neither the fan nor compressor pump come on.

Reply to
lefty

On Sun, 11 Sep 2005 14:47:57 GMT, Puddin' Man wrote: Cap' sounds shot..

Reply to
lefty

Thanks. I've been cleaning contacts, re-wirenutting, etc.

It's getting lo-voltage to the Condensing Unit. Neither the fan nor compressor pump comes on.

What does the capacitor look like? Big cylindrical- shaped thing?

In the middle of the CU elec. box is a spring-actuated device (solenoid?). With no power on, it actuates easily with finger pressure. When the Tstat calls for cool, it freezes up. If I try to push it in, the device hums.

I've got simple and reliable notions about things like open/closed circuits, voltage and amperage, but I admit to a grand level of ignorance as regards the myriad zillions of elec. devices (large and small) in the field. :-)

Thanks, Puddin'

Reply to
Puddin' Man

Reply to
lefty

Thanks. It is silver oval/cylinder GE Capacitor with 3 terminals ('FAN', 'C', 'HERM') and with 8 wires attached. I drew a diagram of the contacts, cleaned the contacts and re-tested: still nothing but the hum.

There's about 14 lines of printed info on the front of the unit. I can't even tell which is the part #.

The first line is 84-09 273. The last line is 42-9611-42505. Do either of these sound like the part #? Where can I get a replacement part for reasonable $ ??

C>>Ifthe capacitor (round silver cyliner w/three wires on it - probably)

Reply to
Puddin' Man

I think I found the part #. Appears to be GE 97F5360, but I Google it and get nothing.

Any/all advice re replacement part much appreciated.

Pudd>>Ifthe capacitor (round silver cyliner w/three wires on it - probably)

Reply to
Puddin' Man

On Tue, 13 Sep 2005 14:50:22 GMT, Puddin' Man wrote: You'll pay 4-5X buying off the internet.. go to your local electrical supply dealer (plumbing & heating).

Reply to
lefty

I'm not a pro: last I looked, they wouldn't sell to me. If I could explain gen'l specs for the unit, do you think Grainger would have one? Reasonably priced?

Thx, Puddin'

Reply to
Puddin' Man

This is Turtle.

Here is the most likely causes.

Cut 24 volt wires by weed eater work.

Ants in or burnt contactors due to short cycling.

A Pressure Safety High or Low has tripped out in the condenser.

Bad 220 volt Breaker or fuse connection at disconnect out side before it enters the condenser.

All in the condenser.

TURTLE

Reply to
TURTLE

--- snip ---

Hallo Turtle!

Nope.

No ants. Maybe a spider or 2. I cleaned/filed contacts.

Its got 150 psi equalized. Should be plenty enought to get it to kick.

Breaker in elec. panel never tripped. I flipped it off/on as part of tests. The outside disconn. looks OK. Made good use of it after I drew a few amperes.

Condenser or capacitor?

Puddin'

Reply to
Puddin' Man

This is Turtle.

In the Condenser unit out side and not the capasitor. It either not getting proper 24 control volt to it , not getting proper 220 volt service to it or something in the condenser unit causing it. It is hard to trouble shoot over the internet.

TURTLE

Reply to
TURTLE

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