Quoting: "Could this be the fan motor? I have a multimeter and know
how to use it. Is there a way to diagnose this problem myself."
Use the ohms scale. Spotting an obvious open or short isn't all that
complicated. Some VOM also have a scale for farads.
Sure, take the cover off and see if there is voltage on the fan motor
That buzzing, does it seem like the compressor is running?
Poke around with a multimeter and you will likely have your answer
If you have a clamp on ammeter, you can try to find out how much
current g goping through the wires, that would also help answer a
question whether the compressor pump is running.
Be careful, but not fearful.
Hey. He's not in a profit situation; he wants a reliable unit. If one cap
has failed, the other is probably drying out, and might need replacement
soon. They are inexpensive, compared to the effort and time of pulling the
unit apart. Why NOT change both while you have it apart?
The only thing I'm confused over concerning this post was the size of the
unit vs its configuration. It's only a one ton unit, but it's a split (not
window unit). I'm not familiar with your locale, so this may be
geographical bias. But the smallest unit we can buy around here (Florida)
in split configuration is a two-ton.
Condenser fans are prone to failure for a number of reasons -- often motor
installers (even the original manufacturers) will forget to take out the
weep plugs, and they corrode from accumulated rain water. But usually if
anything else but the cap goes bad, the shaft will get sticky or seize. The
outside fan relay might also be bad -- or one of the crimps on wiring from
the control board to the motor, or from the motor to the cap(s).
Any thoughts on why the HVAC types seem to suffer from these paranoid
personality disorders that are rarely seen from other trades? Brain
damage due to oxygen depletion from all the Freon they used to dump?
If it's not a window unit, it's a split?? I still don't get what a
There's a compressor just like mine in the trash right now. 27 years
old. Should I go to the trouble to take out the condensor, the fan
motor, the "contactor" or anything else? Normally I would just do so,
but it's alreay about 98 degrees and I don't feel like it.
Who's the asshole? The compressor doesn't have a cap, too?
You didn't read the posts... someone suggested changing the compressor cap
while he was at it, and I agreed. I know perfectly well how many caps a
PSC motor has.
You must have a serious sense of inadequacy to go calling names instead of
posting constructive answers.
If the shoe fits, I guess. It doesn't take much high-level technical
know-how to get to the point of being able to repair hvac equipment. You
guys had to protect your trade status with all the silly EPA stuff. Now it
costs the serious tinkerer a couple-hundred bucks to go take the EPA
certificate tests so he can accidentally blow Freon into the air just like
you do every day on purpose. (sure, he's GOT a reclaimation station... ask
him if he knows how to turn it on).
BTW... could YOU scratch-build your own thermistor-based vacuum gauge for
refrigeration work and calibrate it? I did, and I know several HSMs here on
the metalworking group who have the skills. Bet not ONE of you could.
Could you build a diffusion pump? Bet you don't even know what one is.
Lloyd, I am interested in making a "deep vacuum" gauge, for up to
fractions of a micron. My vacuum pump can supposedly go down to one
micron, IIRC. (nothing fancy, it is a small Sargent-Welch DuoSeal
pump, but it would be interesting to measure vacuum accurately)
Large fractions of a micron aren't really "deep vacuum" like you'd obtain
with an oil diffusion pump backed with a cold baffle and a really fresh vane
pump. But that's still pretty high. You're talking better the range of
what a good, new Robinaire refrigeration pump can do (down to ... oh... 20
microns, or so).
For your range, thermistor gauges are well-suited. Here's a good writeup of
one that will measure down to 0.5u:
However, he doesn't go into calibration very much. Borrow a couple of
commercial gauges, and average their readings to do that. With a small
manifold and carefully assembled, leak-free fittings, you should be able to
pull down and scour your new gauge within an hour or so of pumping.
I'm taking a wag on this but I think a split is one where the cooling
coils (evaporator) are separated from the compressor / condensor
Typical home would be compressor/condensor outside on pad, refrigerent
plumbed inside to/from cooling coils in furnace.
Yep, and many units have separate condensor and compressor caps, in case
your vast experience hasn't exposed you to that, yet. Many PSC air-over
condensor fans have cap pigtails so short you can't get them back into the
weather enclosure, anyway... you have to hang the cap inside the condensor
area, or scab wiring onto them to get back home.