refrigerator repair

Your compressor is worn out.

Plugged freon line would result in a higher than normal high side pressure and lower than normal suction side pressure depending on where the obstruction is.

The average evaporator temp is around -20F depending on where you take the reading, how long the unit has been operating, and what type of freon is used.

You can figure out how much cooling capacity you have by calculating the superheat in the condenser. Google it, I used to know it in my head pretty much but it's been decades since I've had to use it. I usually can tell by just feeling. The compressor outlet should be too hot to hold with your fingers (much warmer than 109F) under normal operating conditions. Either you have a failing compressor which could be noisy or you have insufficient freon. Remember you don't have to be able to see where it is leaking and it can leak an ounce or two a month and you'd never know it until one morning you wake up and your ice is partially nelted.

You need to get some gauges on it to be sure what kind of pressure you have on the high side, I can almost assure you it's too low. You can unplug it then plug it right back in and if the compressor restarts it's low on freon. I would suspect that before a worn compressor especially if the compressor isn't making strange noises. And also enough freon can leak out and you'd never know where it comes from.

Depending on the internal size there isn't a whole lot of freon in these things to begin with and it doesn't take the loss of very much to cause the exact problems you describe.

I'd put a tap on the suction line (returning from the evaporator) and put a few ounces of whatever flavor freon (probably R12) in. Then test the temps. If it comes back to life you have a leak. Then you need to take wifey out to pick out a new fridge.

hey Meat Plow, thank you for your reply. i performed the test you suggested, turned refrig on for 5 minutes, unplugged it, plugged it back in, the compressor would not start until after 3 cycles of the thermal overload protector. i deduct this means there is adequate freon (it only has 4.000 oz of R134a), especially since the compressor outlet temp is so low (possibly meaning that line is not plugged. (and i have read that plugged lines are rare.)

i did not mention in my post, that over a year ago, the compressor began having a rather loud noisy startup, which quietened after about a minute. at that time, i asked a refrig tech about possible noisy reed valves, and he suggested i continue to run the refrig until it quit. so that is where it stands now, still with a noisy startup, but with inadequate cooling.

i tentatively conclude that i need to order a new compressor and drier. >> i am trying to decide if i have a failing compressor or a plugged

If this unit is old enough to have a separate bi-metal thermal overload switch and electromechanical start relay, check out the overload switch as they can fail by self heating and that gives you some really strange load sensitive operation. Our 1980's Whirlpool had that problem, where it would run OK until a defrost cycle and then would sit there overload cycling (a second every minute or so, up to several hours) and them, like magic, just go ahead and work fine until the next defrost.

The replacement was a combined overload/start relay that appears to work like a TV set degauss (using posistors or something like that). About $50.

Mark Zenier snipped-for-privacy@eskimo.com Googleproofaddress(account:mzenier provider:eskimo domain:com)

$50.

Of course not, this is Usenet. ;-)

Well, so maybe it will help somebody else reading the archives.

Same brand. The basic symptoms were the same. A change in the sound at startup, and not keeping temperature were features of my unit, too. (The difference seems to be that my fridge would get cold SOME of the time). And your unit did a series of overloads at the start of your test.

The point is that a weak overload switch will give you symptoms that appear to have nothing to do with its normal function. (The damn thing isn't supposed to turn itself off, or if it does, it should do it consistently).

The intermittent nature of the fault, where it would sometimes run fine and sometime it wouldn't, would make you think it was something different, unless you were listening to it while it was going through its short cycles, which it only did about 5-10% of the time.

Didn't show up worth shit on an ohmmeter, either.

If I'd managed to get a pro out to look at it, he probably would have said junk it, or get a new compressor. The one guy I called wouldn't even bother coming out. Probably figured, correctly, that it would be an unprofitable waste of his time. So I fixed it myself.

(A side question. Is is really worth a couple of hundred bucks and a bunch of your time to fix a 10-15 year old appliance?)

Mark Zenier snipped-for-privacy@eskimo.com Googleproofaddress(account:mzenier provider:eskimo domain:com)