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Hey fellas....New to this site and hope I can get some info on my issue.I'll try to be brief, but I know the more info you have the more you can help.
Ok..... here goes......True brand refer..... Glass front swing door.... the kind you find in a convienence store.Tecumseh compressor...single phase.
A few days ago I went into the garage And heard a humming/buzzing coming from the unit.I unplugged it and pulled out the compressor from underneath, and it felt hot.Everything was clean as I make it a point to regularly vac the dust being it is in the garage and I know it needs air to keep it cool.
I let it cool down, plugged it in an it fired right up.Went about doing some yard work, and about 10 minutes later ,came back in and it was humming/ buzzing again.
Unplugged it. Did some research on the laptop and found out a couple of reasons for the issues. (1)- bad starter relay, (2)-bad start cap, (3)- bad overload relay, and (4), and I guess the worst, bad compressor.
Called the local refrigeration supply store and spoke with a guy there, and explained my problem.
He was leaning toward the start relay,but informed me if I was already in there it made sense to replace the start cap (inexpensive),to rule it out as my problem. Bought both parts.He also told me that if I was seeing an arc when the humming stopped, the overload was doing its job, as it was discharging . Also no rattle when I removed it.
I replaced both parts being careful to replace them the same way they came off. (always take pics with my phone for reference)
Plugged it back in anticipating my repair to be successful,BUT..... It continued to do the same thing.
More research, and I found I needed to test the compressor by ohming it out. Got the multi-meter,held one probe on the top pin on the compressor(where the overload is connected), and put the other on the bottom left pin and the reading was 10.8. Probed the other pin and reading was 1.4. I assume the higher is the high side and the low reading is the low side? I then put both probes on the two lower pins and the reading was 11.3, the total of the first two readings+ or-. I was told that this reading confirmed that the motor windings were still good.
If I tested everything correctly, and thats a big if, why is the compressor still humming? Is there something mechanically wrong with it? Thanks for any help I can get!
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Rank: Advanced Member
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Joined: 9/10/2007(UTC)
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Compressor winding dc resistance only confirms they are not blown open, and usually the higher resistance winding is the start winding, usually lower left.
If the compressor starts humming when cold and the condenser coils start to get hot, your compressor is running. If it stops later, it might be drawing higher current due to varnish buildup, amprobe would confirm. Either that, or the windings have shorted turns which causes motor stall when heated up. When it stalls, it will draw run current and periodically try to start, then shut down on it's overload.
It may be possible to dissolve varnish with Supco 88 but it has to be carefully injected into the system.
To replace the compressor is rather expensive but the unit is worth it.
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Rank: Member
Groups: Registered
Joined: 4/12/2012(UTC)
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Update...... Yesterday, I decided to do some more work/ investigating on my problem. I Pulled a vacuum on the system and recharged with new oil and r-134. Low and behold the compressor fired right up! The refer temp came down about 10 degrees in about 20 minutes..... But then the compressor shut off and went back to doing the original problem.... trying to start, then overload would kick it off. I shut it down. let everything cool down(compressor was pretty hot), turned it back on, and it started, but like the first time, only for about 15 minutes. Compressor gets quite hot.... I think too hot. Fan is blowing good, so anybody have solution to what problem is. I hope that because the compressor started, I can rule out it being bad..... or can it start but still be the problem? Thanks Bill This morning , sunday , after being off all night , it fired up and has been running for a half hour now, but I expect it to shut off soon. Thanks Bill
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Rank: Member
Groups: Registered
Joined: 4/12/2012(UTC)
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2nd update.... Ok this morning (Sun), after about 50 minutes of operating fine, and compartment temp dropping roughly 15 degrees down to around 45, Compresor shut off and will not start again. So I am now believing it has something to do with compressor getting too hot, but because I dont know enough about refrigeration, I am left stumped. Seems like when everything is cooled down, works good..... heats up and I got problems. Is this a problem that is typically caused by something such as low refrigerant, thermostat, compressor ....... Any help from the experts?.....I all ears! Bill
P.S The label on the inside of the fridge says 12 oz. of refrigerant and thats the amount I charged it with. Also added 3 oz. of pag oil.
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Rank: Advanced Member
Groups: Senior Expert
Joined: 9/10/2007(UTC)
Posts: 9,586
Was thanked: 2 time(s) in 2 post(s)
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If you failed to replace the dryer, you might have moisture in the system and the cap line is freezing up.
I would invest in an amprobe and monitor compressor current. If the cap line is freezing up the current will go way below nameplate rating.
It would be wise to unplug it when this happens, a clogged cap line will eventually damage the compressor.
If varnish buildup, or other internal problem, the current will go up before it shuts down.
Sorry I am late in responding, for some reason, I am not allways getting email from this site.
You can heat up the cap line with a propane torch to remove ice clog, but diagnosing internal compressor problems is difficult.
If you do confirm a clogged cap line, you can allways precision cut it and blow it out with high pressure gas. It's possible oil got in it.
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