1951 Frigidaire Rely Problem?

kmivens

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I have an old 1951 frigidaire that I inherited several years ago and it has been serving me quite well as an extra refrigerator. However, over the past couple of days I have noticed a slight issue. It is still keeping thing cold, but I am noticing that it is having trouble starting up. I will hear the compressor kick in, but it almost sounds like it stays running on the starting circuit. After about 3 seconds, it will trip out under overload. It will usually do this about 2 or 3 times and then it will startup and runs fine. Sometimes it will startup the first time. I was wondering if this sounds like the start/run relay could be going bad or if it might be an indication that there is something more major going on. Is there any way that I can test the relay? It has been a great fridge and I would like to keep it going if I can. Any help would be appreciated.
 

rickgburton

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I'll need some pictures of the compressor or a wiring diagram to see what I'm dealing with. Even a model number might help but probably not. Whatever you can show me will help.
 

kmivens

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Thanks Rick. I snapped a photo of the wiring diagram and of the compressor. It actually seems to be running fine tonight. I haven't heard it short cycle yet this evening. The model number 5890072. According to the model number plate it was manufactured in Nov 1952. I hope this helps.
 

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rickgburton

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That compressor uses a "Hot Wire Relay". It doesn't use an overload because it uses a wire that's sensitive to current changes. I'll tell you how to check it but you should be comfortable working with live electricity and you should be very careful working with those old wires because the outside coating/casing will be extremely brittle and will crack and/or fall off the wire easily. On a Hot Wire Relay, there are "Dummy Posts". The wires on the "Dummy Posts" are under the screws just to make wire connections and are in no way connected to the relay itself. You're only concerned with the three wires to the relay proper. Look closely at the relay itself. You'll see the markings, "L" for line, "M" for motor, and "S" for start. Remove the power source from the machine. Remove the wires from the relay under the terminals marked "L" "M" and "S". Connect wires "L" and "M" together or fasten them under one of the screws on the relay for convenience. Have someone plug the machine in. Cautiously touch the "S" wire to the "L" and "M" wire. If the compressor starts, immediately remove the "S" wire. If the compressor continues to run normally the relay is causing the problem. That style relay can be replaced with a newer solid state style relay without any problems.
 

kmivens

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Hi Rick: I ran the test that you proposed and the compressor does start up and run correctly when the "S" wire is touched and removed from the other two wires. I guess this would be an indication that the relay is starting to fail. Is there any type of universal relay that you would recommend or do you have any recommendations on a relay that I could install? Thanks again for your help.
 
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rickgburton

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This one will work. Since that compressor doesn't have pins you'll need to pick up some wire terminals at your local home center. This one is for a 1/3 hp to 1/2 hp. Look on your compressor and make sure it's not any bigger than that. I'm almost sure it's not but almost don't feed the bulldog.

Start Relay RO41
Compressor-Sealed-System-RO41-00985753.jpg

This is how you wire it:
Solid State Rewire.jpg
 
G

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I realize this is an old thread but I wanted to point out that the correct original equipment relay for this era of Frigidaire refrigerator is still available on Ebay. Several sellers have them. You need to know what the compressor horsepower rating is and the location of the terminals on your old relay. I recently replaced the relay on my 1950 Frigidaire model DM-90P with a correct one I bought from Ebay. Frigidaire used the same relay over many years and models so they are out there. These relays are repairable too if you have the skills to do so. What happens is the contacts on the start circuit wear down and get stuck together. This prevents the start winding from dropping out of the circuit when the compressor motor comes up to running speed. This trips the overload. Replacing the burned out contacts in the relay solves this problem. There's videos on YouTube that show how to do this.
 

birchy

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I have a vintage 1951 General Motors Frigidaire and I need to replace the relay. 5850824 1/8hp YT
I looked on eBay but couldn't find the same one. How would I find a universal relay that would replace this one?
 

birchy

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Thanks so much. We just got the relay in the mail today, but can't figure out how to wire the new relay to our vintage refrigerator. I can't find anything on youtube. Any help would be much appreciated. Not sure where the red and white wire go.
 

rickgburton

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Take a couple pics of the wiring that's on there now and post them here. Take a few pics of the inside of the refrigerator.
 

birchy

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1951 General Motors Frigidaire.png
This diagram shows the same wiring that our fridge has. The relay is located in the front of the fridge at the bottom. General Motors Frigidaire (~1951).
1951 General Motors Frigidaire.png
diagram shows the same wiring that our fridge has. The relay is located in the front of the fridge at the bottom. General Motors Frigidaire (~1951)
2016-4-23 Groton (9).JPG
2016-4-23 Groton (10).JPG
 
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On the diagram above, A=Common, B=Start, and C=Run. Hope that helps!
 
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