Air Conditioner Transformer Question

Ok I believe that a transformer changes voltage from x to y, either raising or lowering the voltage as required for the application. For example, the a/c charger for my phone lowers the voltage, and an inverter (like to power my laptop in my car) would raise it. If I am wrong please set me straight.

Now to the big questions . . . Is there a transformer located in the condenser (outside part) of a central air conditioning system. Is there a condenser unit manufactured in the last 15 year that requires replacement of the condenser if the transformer fails, as opposed to just replacing the transformer itself.

I am asking because my friend was told her condenser needed replacement because the transformer was bad. Yes she did have it replaced. I am asking because this sounds "suspicious" to me. I imagine that it should be relatively easy to procure a replacement transformer and install it, instead of replacing the whole condenser. She has gone to sleep so I do not have specific brand or type info except that it is what most people would call "central air" in a home about 15 years old.

I am by no means an expert so hopefully more knowledgeable people can help.

Thanks in advance, Dan

Reply to
cornbinder595
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You may believe that, but home repair is not built on faith.

An inverter changes DC to AC. Another part of the circuit might change the AC voltage.

Do you mean the entire condensor box with everything inside? That's 2 feet cubed or so?

Or is there any chance your talking about the capacitor (which in radio is often called a condenser)? Which is about 8" by 4 inches, usually with 3 wire connectors on one end.

But you mean the entire box or you wouldn't be posting, right?

I don't think there are any transformers in the condenser cabinet, in any unit I've seen.

OBSOLETE paragraph: Isn't there a wiring diagram on the inside of the cover panel? Or maybe a manual folded and stuffed in the cabinet under that panel? Oh, I was thinking the other meaning of condensor, and her outside unit has been replaced by now.

I have only experience with oil and gas heat with electric AC, and there's a small transformer inside the house, in the furnace, that provides 24 volts for the control circuit (thermostat, furnace relay, AC solenoid).

Most failures are "opens" and that woudln't damage anythign, and even if the voltage were too high, it wouldn't damage the whole outside unit because it only powers the solenoid in the outside unit. It woldn't even hurt that.

However condenser units do fail sometimes of course. Why did she call a repairman in the first place? How old was the system? Did it work at all?

I am an amateur too. And might be wrong in almost anything I say.

Friends of mine are selling their home and they had a guy who fixed up another home for sale (and did a good job according to the friends of my friends who first hired him) come over, and one of the things he said was that they needed interconnected smoke alarms in every bedroom to comply with code, and that he could get wireless ones so they didn't have to run wires.

Turns out, they only need one battery powered smoke alarm on their first floor and one in the basement (no other floors) People do lie, it seems.

Reply to
mm

I was wrong thanks for setting me straight.

Right

We are in different cities (5 hours away). I wasn't there, and she wouldn't have a clue about a manual. From our conversations it sounds like the entire outside unit was replaced. We also talked about making sure both the interior and exterior units matched in tonnage

Ok that akes sense.

Problem was no cold air from the system, blower worked. About 15 yo worked since she bought the house in May.

Sound as if you are a better amateur than I

That last line is my concern, of course.

Thanks again, Dan

Reply to
cornbinder595

There may be some semantic/communication confusion with the fault described but if indeed the only fault with the unit was a transformer then it could have been replaced as a component. I would perhaps re examine the information you have received, then again there are many sharks around in the service industry who seem to home on on female customers :-(

Rheilly P

Reply to
Rheilly Phoull

As a relatively new HVAC tech, I've installed equipment for a couple years, and trying to get started as a service tech. I've mostly worked on central AC, where the heat is natural gas, or oil. Serviced very, very few heat pumps.

That said, I've never seen a transformer in the outdoor unit. And transformers are easily replaced. There is typically a transformer in the furnace. The thermostat calls for cold, and the circuit board sends a 24 volt signal out the small wire, to the outside unit. This low power signal activates a contactor, which connects the 220 volt power to the outdoor unit.

It sounds like there is a communication error going on, here. It's possible she remembered the wrong word (transformer, instead of compressor or contactor) or that the guys on the job were less than honest with her.

Reply to
Stormin Mormon

I think the tech turned his meaning around. What he thought was: "I want to replace the condensing unit, so let's claim "X" is bad."

The outside condensing unit is made up of several components: Compressor, coil, tubing, dryer, electronics, wiring, fuses, etc. None of these components is a "transformer."

The only possibility that comes to mind is the "transformer" on the utility pole. If the light company's equipment went really bad, it is conceivable that fatal damage could be done to the outside condensing unit. If that was the case, the utility company would cheerfully pay for any damage.

Reply to
HeyBub

Sounds most likely to be a scam artist. There is typically no transformer in the outdoor unit, and should there be one.....certainly replacing it, rather than the entire condensing unit, makes much better sense.

It is fair to offer the opinion that a 15 year old condensing unit may indeed need replacement, and the choice of descriptions given by the repair guy as interpreted by your friend may have become a bit confused in the "translation".

I certainly does sound extremely suspicious as you describe the situation.

Smarty

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Reply to
Smarty

The Trane 19I has a 240V to 24V transformer in the condenser. As far as replacing the whole condenser because the transformer wen bad, only if you are a hack or a crook.

Reply to
Nate Certifeid Heating and Air

Lots of good advice in other posts. In short, there is at least one transformer in the AC system and it is commonly in the indoor unit. It can be in the outside unit and there can be one in each unit. You can hold it in the palm of your hand. It is a common failure item, can be replaced easily, and is inexpensive. A complete outside (condensing) unit should not be replaced if only a transformer is bad.

It is a different story if the bad part is a "compressor".

Don Young

Reply to
Don Young

If it's central air, the only transformer would be for the thermostat operation. Ac's don't typically need transformers internally except for thermostat conrols, things like that.

Reply to
TWayne

Hey Einstein, What exactly do you think pulls in that funny looking contactor thing-a-muh-bob? Bubba

Reply to
Bubba

That should be the 24VAC from the indoor transformer, switched by the thermostat.

Reply to
Mark Lloyd

Not correct, Some units do have a transformer in the outdoor and indoor units.

Reply to
HVACTECH2

I wouldn't call that a lie. That is required by current code for new construction, but not necessarily if one is selling an existing structure. Remodeling, well, that is a grey area likely depending on the extent of the remodeling, and the interpretation of the AHJ.

nate

Reply to
N8N

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