Compressor Overheating?

[Rob_Feature]

So frustrating.  I've had the compressor out of my Westinghouse WB78 twice, taking it over to JohnieG for repair....and the same thing seems to happen every year (this is the third year with this machine and it's never consistently worked).  Certainly not Johnie's fault, but I don't think it is (or ever was) related to a 'leaky' compressor.

The unit will cool for maybe a week or so, everything will seem fine.  Then one day I'll open it up to refill it and the fan is blowing, but the inside air is warm/hot. (I noticed this happens more often on really hot days, but today isn't hot and it happened today).   At this point the compressor DOES seem to be running (fan for lower section is on, etc) but it's hot to the touch.  

It seems like if I leave the machine off for a given amount of time, say a day or a week or whatever, then plug it back in, it resumes cooling again.  (I haven't tested this in an organized way to figure it out exactly)

I had thought it might be the poor electric in my garage, so this year I moved it over to the house for better electrical.  I read somewhere that if it can't draw enough current, there's a safety of some kind that shuts down the compressor.  That's my best guess as of now, but I have no idea what to do.  So frustrated I feel like getting rid of this thing even though I love it.  I've already poured too much money into trying to get it working that I hesitate to do more...

Any ideas on what I can try?

PS:  Possibly related: I noted in another post that the ground protect kept tripping previously when I added a 3 prong cable.  I thought maybe it stopped recently but it could be that certain conditions trip it and something is wrong.

EDIT:  Just an update that it looks like the 'thin' cooling line (capillary tube?) is getting frosty as it runs beside the 'hot dog' in the upper compartment, but I don't see any frost on coils for the upper fan (I thought they should?). What should I be looking for in terms of what should frost, what should be cold, etc?

[SodaShopNick]

I am not an expert, but had a similar issue with a CAV72 in my garage.  It ended up being a slow leak in the line somewhere.  Moisture would get in and freeze up over time and the air would then go from cold to warm.  I would unplug it, the freeze in the line would thaw out, and then it would cool again.  Then again over time it would do the same thing.   The amount of time between cold air and warm would depend on how ling it took the line to freeze up again. 

[Rob_Feature]

Hmm....interesting.  Seems like something Johnie would have detected when doing a recharge (and actually he did 2 recharges, looking for leaks both times)? Or could something like this go unnoticed?

[johnieG]

Just because a leak wasn't found doesn't mean the ol' gal hasn't developed another somewhere in the meantime, old steel condenser lines & coils get rusty & develop pin-holes over time.

the compressor uses the Freon in the system to get rid of 90% of its own internal heat, so a low charge will cause both the bottle compartment to go warm & the compressor to overheat, plus it (the compressor) wont ever shut down because the unit cant get down to temperature. again leading to  hot compressor motor.

A leak in a system will also draw in water vapor to contaminate the oil, which can lead to internal ice blockage on the capillary tube. or just some micro size piece of crud in the oil of a 60+ year old system.

insufficient cooling & light frost only on / around the capillary line or just around the point of expansion ( the copper bulb where the capillary tubing joins the evaporator coil) is usually a sign of a light charge. only putting a set of gauges on the system & seeing the differential pressures between the high & low side will help diagnosing the trouble & injecting some UV dye will also help pinpoint the leak if it's too small to use an electronic "sniffer" on it.

[Rob_Feature]

Thanks Johnie, I appreciate the feedback.  After having it charged twice, is it time to just put in a different cooling unit?  I'm afraid of doing it again and ending up with the same problem for a 3rd time.

[johnieG]

I suppose if you have a good used cooling system out of another identical model to swap with, or you can repair/ rebuild your deck assembly.

[Rob_Feature]

Thanks Johnie, do you think it's worth having you take another crack at it, knowing that there's probably a small leak to find somewhere? Would really like to get this up and running for good!

I'm thinking first I'd let it thaw, pull it out of the machine, and let it run outside the machine for a while to ensure it's not something machine-specific (ie. wiring, etc) that could be causing it.  Would that be a logical next step?