Surely there is a point at the Compressor Motor to detect the presence of power, if there is then refer to the Bi-metal.
I assumed the meaning was a given if the fan is running OK?
Max.

 

Surely there is a point at the Compressor Motor to detect the presence of power, if there is then refer to the Bi-metal.
I assumed the meaning was a given if the fan is running OK?
Max.

The compressor has 3 terminals, start, run, and common...with a bimetal in the common leg. It is fairly common that a wire burns off at a compressor terminal, to the point that there are repair kits just for that failure. When jellytot says he does not know which capacitor is for the fan and which is for the compressor, I expect that means he did not trace the wires, therefore, he probably didn't take the plastic cover off the compressor to inspect the connections.

 

So the bimetal is exposed? I was thinking of the types embedded in the motor itself.
Max.

 

No, the bimetal is not exposed. It is in the common leg, inside the compressor.
We try very hard to never let the bimetal open because sometimes it doesn't recover. Then the whole compressor is toast.

 

We try very hard to never let the bimetal open because sometimes it doesn't recover. Then the whole compressor is toast.

We ?
Do you manufacture those ?

 

We ?
Do you manufacture those ?

No, I just designed and repaired air conditioners for the last 40 years.
We designers and repairers try not to let the bimetal get involved in saving the compressor. That's why compressor re-start delays were invented.
That's why high pressure lock-out switches are installed.
That's why Carrier used a current monitor board on the common lead.
All to keep from having the bimetal open as a safety device.

 

No, I just designed and repaired air conditioners for the last 40 years.

May I ask your opinion?
The issue with the AC is that it short cycles (compressor ~30 seconds on, ~1-5 minutes off). It doesn't do much to cool the place down, and we're sweating all the time. It will do this for days, and then it will stick to long cycle (compressor on all the time). When on the long cycle, doing anything (e.g. adjusting the thermostat, or turning the unit on/off) will start the unit short cycling again, but eventually we have to do something because it gets too cold in the place. The AC did this before I replaced the capacitors, and afterwards. Right now, it's "stuck" doing the long cycle. What do you think may be wrong?

 

It sounds like a bad thermostat right now.
Then again, you have not revealed the brand name, the model number, the size in BTUs, a photo of the unit or the room it's in, or whether it has electronic controls. All I have is your testimony, and I know that people often have wrong beliefs about how an air conditioner is supposed to work. If I walked into that room, I would know in a minute or two, but it's only you in that room.

 

It sounds like a bad thermostat right now.
Then again, you have not revealed the brand name, the model number, the size in BTUs, a photo of the unit or the room it's in, or whether it has electronic controls. All I have is your testimony, and I know that people often have wrong beliefs about how an air conditioner is supposed to work. If I walked into that room, I would know in a minute or two, but it's only you in that room.

The thing is OLD. Likely as old as the building (I estimate from the 70's-80's). No electronic controls: Just 5 push-buttons (Cool and Heat, Low and High, Off) and a temperature dial (turn left for warmer, right for cooler).
Says Mcquay on it. Can't find a model number. No idea the BTU's. Unit is in the main room. After doing some research on the net, our unit looks similar to a Mcquay EA incremental conditioner. I took a picture, but I can't seem to upload it for some reason. But it looks like the image below.

 

The knob for temperature is connected to a mechanical thermostat. That box has a copper tube coming out of it. That is the thermostat bulb.

As for, "sometimes short cycles and sometimes sticks "on", that sounds like a bad thermostat.

 

As for, "sometimes short cycles and sometimes sticks "on", that sounds like a bad thermostat.

OK, thank you! Hmmm... tempted to open her up and look inside.