pcc1
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Posts: 7
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Post by pcc1 on May 30, 2020 2:23:06 GMT
Our CA-2 stopped running, and I checked it for NCGs as I hadn't bled it in 3 years. I couldn't get the motor to run for more than 30 seconds without shutting off, so I slowly bled it over the entirety of two days, eventually putting an old style electric defroster in the freezer compartment to help get pressure up as I couldn't get the compressor to run. Because of the extreme volatility of methyl formate I have a feeling I might have overbled the NCGs and started bringing up some MF with them - my wife at one point noticed a smell of almonds briefly, which I did not notice. Not knowing what MF smells like, I checked over other things, at one point hearing what sounded like a "clunk" in the compressor as of something freeing up, then I checked the start motor relay. The inside of the relay cover was black with soot from sparking, there was discoloration on the copper, and a loose central point which my wife polished and very finely re-soldered (she trained in fine metalwork). Afterwards it started with only the tiniest spark and a quick release, but once the interior temperature came up to setting 5 steadily it would run for about 8-10 minutes and then be off 6 min or so, then repeated this way over the last two days. This evening in one cycle it hummed and stopped; I turned it off, waited a couple of minutes, turned it back on, there was the hum and then the motor started sloooowly but came up to speed and sounded normal. I think the motor was overheating from insufficient downtime due to insufficient refrigerant in the system to compress - would a suitable course of action be to add 1/2 lb. of MF and try again, or something else? It ran splendidly until this week. Any advice will be gratefully received.
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Post by elec573 on Jun 3, 2020 23:40:11 GMT
Have you checked the heater I saw no reference to it in your post . The off times are to short when it was running. Cas are know for the seats to be worn . As for the slow starting it may not be engaging the start winding. But make sure you’re heater is working before you do anything . monitortop.freeforums.net/thread/81/ca-service-manual |
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pcc1
New Member
Posts: 7
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Post by pcc1 on Jun 7, 2020 3:06:34 GMT
I replaced the heater 2 years ago, so I believe it's still good. The start winding engages and releases quickly at first, but as I said, the cycles are short, and I really think I overbled the unit. Before the unit stopped - which I now believe was mostly due to arcing in the relay, which I have fixed - it was running absolutely perfectly. It will start readily now and with running the meter reads 2.27 amps and 116.7 volts draw, but I haven't added any MF yet so I don't want to run it further with short cycles and overheating the motor windings.
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Post by elec573 on Jun 10, 2020 4:50:25 GMT
Just to rule out the heater I’d do a check on it , with the switch turned off and fridge unplugged , check it at the prongs . With an ohm meter if you get a good reading of around 1 k
it’s probably good , but if it’s going all over the place then I’d say it’s bad . That way we can rule out the heater just to be sure.
It’s unusual to lose to much refrigerant when bleeding a ca , if you follow the instructions from the dr manual. Not saying it’s impossible but not usual .
How is your frost line on the header inside,has it changed from how it was previously? If it was low on methyl formate I’d think the frost line would drop on the evaporator from
its previous line .
‘Your off times are too short could indicate a worn seat , not stopping the refrigerant from circulation.
Look through the ca section and see what description best fits your problem.
These machines are old and need some special care to keep them working.
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