Rooftop Air conditioner/Unnecessary Wire????

[larry dtimothy]

> In a message dated 98-08-16 22:00:51 EDT, you write:
> The best I can tell from the paperwork and what I understand that You're
> saying, this is our culprit. It is the largest of the three. (30uf)
> The wire in question goes from here to what appears to be a relay.

> Tim
> It should be the biggest. 30 micro f about right. The relay is the start
> run relay. It starts the compressor on the start cap and then switches
> it to the run cap. The relay could also be bad but from my experience
> the cap is more likely to fail. Low voltage at campgrouns causes that.

Thanks Arch,
I now know the capacitor was at least part, maybe all of the original
problem. It has been replaced and the A/C works fine WITH or WITHOUT
the wire mentioned. I was trying to understand the purpose of the
apparently unnecessary wire, which, when attached will not let the A/C
function with the faulty capacitor installed.
Tim

 

[donald w. miller]

My guess is, though the compressor motor runs without the capacitor, it
probably draws more current and the compressor windings run hotter. I would
suggest you make certain it is properly wired.

I worked one summer for Westinghouse as an intern in their industrial A/C
design lab. The test cells were always well ventilated because when a
compressor using R22 fails it can produce Phosgene, a highly poisonous gas.
While I was there, we had compressors fail and blow out the seals around the
electrical connections. There is also a flash fire as the oil comes out of
the system under pressure and burns violently.

Those guys had enough respect for the potential danger they made a lasting
impression on me so 45 years later I still prefer R22 compressors mounted
outside the house over those in bedroom windows.

On the other hand, I have never heard of it being a problem outside the lab
because the thermal switch keeps it from occurring.

I have several A/C service oriented books which do not mention it so I do
not know if this is well known among people who service A/C units or just to
those who design them.

Next time you hear an R22 compressor thermal switch click, you can count
among your blessings the fact that it worked.

Don

- -----Original Message-----
From: LARRY DTIMOTHY
Date: Monday, August 17, 1998 03:27
Subject: Re: GMC: Rooftop Air conditioner/Unnecessary Wire????

>> In a message dated 98-08-16 22:00:51 EDT, you write:
>> The best I can tell from the paperwork and what I understand that You're
>> saying, this is our culprit. It is the largest of the three. (30uf)
>> The wire in question goes from here to what appears to be a relay.
>
>> Tim
>> It should be the biggest. 30 micro f about right. The relay is the start
>> run relay. It starts the compressor on the start cap and then switches
>> it to the run cap. The relay could also be bad but from my experience
>> the cap is more likely to fail. Low voltage at campgrouns causes that.
>
>Thanks Arch,
>I now know the capacitor was at least part, maybe all of the original
>problem. It has been replaced and the A/C works fine WITH or WITHOUT
>the wire mentioned. I was trying to understand the purpose of the
>apparently unnecessary wire, which, when attached will not let the A/C
>function with the faulty capacitor installed.
>Tim
>