Old GE Compressor

[MrFoodScientist]

So now that I have time to get back to my vintage fridge that I bricked, I have some confidence that I can patch the pinhole with some aluminum solder, but before I do that I want to be sure that my compressor is serviceable. Does anyone have any experience or advice for this?

Here is my compressor, the end has a threaded port with a little bolt that covers the hole. There is a port on the compressor that was covered with a plastic shrink seal that I peeled off (blue circle) and there is a port on the condenser coils that looked identical to the compressor port before I tore the seal off (red circle)
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Having taken off the bolt that covers the port, it uncovered a bristol splined insert of some sort that looks like it makes up part of the valve.

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I'm not sure where to go from here. It would seem that it would have to be removed to vacuum the system, but if that's the case then I'm not sure how one would then replace it without opening the system again
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[501irishred]

About the thing you can do before charging is to check that it's ok electrically speaking. There should be three wires going into the compressor marked R, S, and C. Using an ohm meter, measure between each terminal. The value you read between R and C plus value between S and R, should total the value between S and C. Also verify you have an open between each terminal and the metal case of the compressor.
Have no idea what the area in blue is (before my time, at least in HVAC respect). Looks like it may be a way to actually service the valves, "disposable" compressors may not have been in fashion yet.
As for pulling a vacuum and charging, you may need to add some service ports. If so this is no different than 98% of modern consumer refrigeration.

 

[mikescooling]

I am old and never seen a pot that looked like that. I would braze hole and pull a vacuum or charge with N2, again to see if their are more leaks. As stated above, check the winding of the compressor for, open, shorts, or grounds. What refrigerant does this use and how much does it cost? Lots of times these restorations are new guts. Sorry can't be more help, I've been out of the trade for some time.

 

[MrFoodScientist]

This is a 1945-1949 ish GE refrigerator, so I figured it would be a longshot. I can hardly find any information online about these old beasts. I know it worked fine before I replaced the insulation, so I'm not too worried about the functionality of the compressor. It would be wise to check the wiring, though. I already replaced a lot of dry rotted stuff. Some wiring was still really flexible, though, so I left what looked well insulated.

I'll have to see if I can find any electrical terminals. There is a cord that comes out of the compressor and attaches to the relay and a capacitor, is that where I should check for shorts?

This takes R12, which I know is pricey, but I do know an HVAC guy that has some, I just don't see him very often and wanted to do all the legwork before I called him to come over. He lives about 40 minutes away. So mainly I just wanted to see if anyone out there has seen these and how likely it is that I'm getting in over my head.

 

[501irishred]

If it was running/cooling prior to beginning restoration I'd say you could skip the resistance checks on the compressor. Agree with Mike; patch it up, pressure test it, vacuum, charge, rock your vintage cooler! Sounds like you've already put in some serious work. In for penny, in for a pound!

 

[The10mmKid]

<snip> and there is a port on the condenser coils that looked identical to the compressor port before I tore the seal off (red circle)
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How about a pic of this port?

Most small systems are factory charged and have no service ports.

Best fix is to repair the puncture. Purchase a line piercing service port kit. Vacuum it and charge it to the weight specified on the nameplate.

'da Kid

 

[501irishred]

Purchase a line piercing service port kit.
'da Kid

Piercing valves are a necessity to recover refrigerant from a closed system, but IMO is asking for problems (leaks) to leave as a permanent solution. Certainly a solution if you don't have tools/skill for a permanent install, but should be easy enough (for friend that works HVAC) to braze in a schrader valve.

 

[mikescooling]

That brings up a good point, we used a set of Linesman's that had a piercing valve built into it, to recover the refrigerant. The use of some tool to recover the refrigerant, may be the hole your are trying to fix. The coils are almost always what leaks not usually the pipes.

 

[MrFoodScientist]

How about a pic of this port?

'da Kid

I haven't torn it open yet, but the shrink seal is still covering it as seen in the first picture. I'm assuming that it is identical to the other, but I may tear into it later just to be sure. It hooks directly into the condenser lines that run up and down the back panel of the fridge. (panel as seen in kerber's thread) I haven't even thought that it might be different. I'll see if I can get a picture of that one if it ends up being different.

I did find out that this tool is what is used to charge it. The whole tool attaches to the port on the compressor. Then the T-handle unscrews the bristol splined insert to open the valve. After that, the schrader valve on the side of the tool is used to vacuum/charge the system. The T-handle then threads the insert back in to close the valve and the tool is removed.

Most small systems are factory charged and have no service ports.

'da Kid

Kid, I have noticed that as well. I'm guessing that's because most small systems that are in use currently are not yet approaching 70 yrs old and were built after the concept of planned obsolescence really caught hold.

Thanks for the heads up on the piercing valves, but I'm with 501irishred in that I don't think putting more holes in this would be a good idea.

The hole I'm trying to fix is a pinhole leak where the copper tubing meets the aluminum evaporator. Apparently I wasn't careful enough when I removed the sealed system to replace insulation. I've been told that it can't be brazed because the heat of the flame will melt holes in the thin aluminum long before the copper gets hot enough to braze. I'm told that my only option is an epoxy kit made specifically for aluminum evaporators that I'm trying to track down.

 

[501irishred]

Another alternative to the epoxy is a low melt point brazing rod. I've used several different ones, but the "handy 1, AL 822" is the easiest/best I've used so far IF you can find it (hit or miss around here anyway). Have not found it online as yet, but have found it periodically at a couple HVAC supply, and welding supply stores. The melt point is around 800 deg F, and can be used with a map gas torch (maybe even propane). Still have to be careful, but makes a very good repair.

 

[MrFoodScientist]

I had considered that route as well. The MuggyWeld SuperAlloy 1 with a meltpoint of 350° was pretty tempting, but $60 for the kit compared to $20 for the epoxy kit makes the epoxy look like the way to go.
I talked with my HVAC friend and he recommended the epoxy. I've also never done any brazing before and only soldered electronics, so epoxy is probably more within my reach.

 

[501irishred]

You bet! Just like in brewing, the method that works for you is certainly the best.