1953 Frigidaire fridge - Newby questions on cycles, gaskets, mystery shelves...

[italiantuneup]

Hi, long time lurker, slowly backdating the appliances in my 1940s house and the forum archives have been very helpful.

I bought this 1953 Frigidaire SS86 in rough-but-running shape last year. I stripped it, re-insulated, new gasket, gave it a paint job (2k auto-style). I didn't touch the sealed system.

I'm new to vintage appliances but I build classic cars, so I'm expecting a shake-down period to work out the bugs. Apologize for asking so many questions at once, this is stuff I couldn't find in the archives.

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1: Should I make relief cuts in the gasket corners? I read somewhere that they would conform over time, but it doesn't look likely to me.

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2: What does the removable tray with trap door do? A baffle to keep cooled air in the freezer?

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3: What is a normal cycle-time for the compressor?

Starting from room temp, it cycled quickly. 60s on, 60s off. I couldn't figure out why it would have been cycling at all, much less that quickly. The thermostat would be open until the fridge was cold, so I'm curious what is shutting the compressor off. I'm sure the gasket corners aren't helping.

48 hours after I first started it, the off-cycles have increased to 2-5m. On cycle is still only 60s.

The compressor is nice and quiet, but startup is loud. Hearing it start every couple minutes is a bit maddening, so I'm hoping it's meant to have longer cycles!

 

[combo52]

Nice restoration job.

It sounds like the refrigerator is working pretty normally, it will have much longer running cycles and longer off cycles if it was full of food. If you’re not going to keep stuff in the freezer put a bunch of containers of frozen water in it.

As you can see the freezer temperature in these older refrigerators really isn’t suitable for long-term frozen food store they don’t get near enough to zero and stay there.

The flap in the chiller tray you open for colder temperatures down below and heavy use of the refrigerator and you close it for colder freezer temperatures, if you’re not gonna use the refrigerator heavily I’d probably keep it closed.

Trimming at the corners of the new gasket would make it look a little better probably and maybe fit better.

Good luck with it I just know how it works.n

John

 

[rp2813]

I remember my pint-sized '39 Westinghouse drinks fridge would only cycle for about a minute or two at the most.  John's remarks are on point about how your fridge behaves when empty.  My Westy was so small that it didn't require longer run times to keep contents cool.

 

I also agree with John about the baffle.  My '52 Kelvinator has a flap at the back of the tray under the freezer section, and it will freeze drinks toward the back even with that flap down (flap up being the position where more cooling below is desired).

 

[italiantuneup]

Makes sense that an empty fridge would "lose its cool" more easily, I'll transfer my food over. I'm moving over from a modern fridge so the freezer will definitely be full.

The compressor running in consistent 60sec cycles (starting from room temp) still confuses me. I get that once the temperature is stable it may only need to run 60s to close the thermostat, but at first startup I expected it to run for an hour +.

My only experience is with air compressors. My shop compressor will run until it hits the set pressure, or until thermal failure, whichever comes first. Is something other than the t-stat tripping this fridge compressor? Seems odd to me that it runs the same 60s no matter what the temperature inside is. The fridge is still warm, why shut off?

I wonder if any manufacturer tried using anticipators in the t-stat circuit? Would be nice to be able to make the fridge overshoot it's target so it cycles less.

 

[combo52]

Refrigerator running times

On a modern refrigerator the thermostat system actually senses the temperature of the air in the refrigerator. on this older refrigerator the thermostat is clamped to the aluminum evaporator, so it’s not unusual when you plug one of these in for it to only run for five or 10 minutes even, but the air temperature in the refrigerator is nowhere near cold enough for good foods until it’s been on for a while.

Once you put food in the freezer that will act as an Anticipator.

John L

 

[italiantuneup]

"I remember my pint-sized '39 Westinghouse drinks fridge would only cycle for about a minute or two at the most. John's remarks are on point about how your fridge behaves when empty. My Westy was so small that it didn't require longer run times to keep contents cool."

Is that 1-2m for each on/off cycle? It cycles 30-60 times an hour?

 

[italiantuneup]

Got a lot of Frigidaire-specific info from the monitortop forum, figured I'd post it here for posterity. I'll post again when I solve these issues.

My compressor (meter-miser 1/8hp) is definitely not cycling correctly. It should run continuously for at least 30min from room temp, and nothing should stop it besides the t-stat (or an overload fault).

Possible causes:
* YT relay has an overload breaker that cuts power if current draw gets too high. Could be tripping from current every 60s, or the contacts could be damaged and separating earlier than they're designed to. Need to visually inspect the contacts while it's starting and running, and measure current.

* Thermostat is a bit fragile on these, with adjustments that can cause strange cycling. Good news is that the trigger range is adjustable, so I can increase that gap and get less cycling in general. Similar end result to an anticipator. Also can change preload on the bellows to bump that range up or down overall.

* Blockage or air in the closed system can stall the compressor as pressure builds, might take 60s to hit that pressure, which would explain the consistent 60s cycles at every temperature.

Also, watched quite a few YT videos from a guy who collects this era of Frigidaire fridge. I watched him recharge a crusty meter-miser with 152A, then run the compressor for a while with the door open. After 30m the freezer was at 0F, with the door wide open! So long-term food storage should be possible. Link to his channel below.

 

[turbokinetic]

Hi Justin.  Thanks for linking to my Frigidaire repair video. Happy to see that has helped you out.

 

In addition to storing something in the freezer as John recommended, (even a few frozen water bottles will help) you may also be looking at a thermostat which is worn.  There should be "snap action" within the thermostat, which is part of the mechanism giving the differential between the cut-in and cut-out. I've seen these lose the snap-action where the cut-in and cut-out become very close together. It's like the differential has reduced to some small amount; maybe 1 degree or so. That causes the extremely short cycling. When things are working correctly you should hear a distinct "click" from the thermostat when it cycles on and off automatically. It's often loud enough to hear with the door closed. If the thermostat is operating silently, this is a bad sign.

 

The fact that it only ran one minute from ambient temp startup is very odd. That seems like there is something else at play.  If the sensing tube from the thermostat is touching the wrong part of the evaporator (the part which frosts first, at the capillary tube inlet) it can cause some very short cycles. There should be a specific place where the thermostat sensing tube attaches to the evaporator. It shouldn't touch any lines or other components other than the evaporator shell where it is designed to clamp down. 

 

If you have any reason to suspect the compressor is unhealthy, you might want to use a current meter (such as a Kill-A-Watt) to see what the running current is.  It should be less than 3 amps during the middle of the cycle. If it's much above that, you can expect the overload breaker to trip after a minute or so. I doubt this is the problem though.

That looks like the silicone door gasket from Antique Appliances in Clayton, GA. While it does look great, the silicone material will never conform and lay flat like the vinyl gasket does.  Frigidaire had "pie cuts" in the inside area of that gasket from the factory. This was there to help prevent the puckering and wrinkling you are seeing. This is gong to be necessary with the silicone gasket. I did a short search and found the attached picture at RetroRefrigeration and borrowed their picture to show the factory pie-cut gasket corners.

 

As far as sealed system blockage or air in the lines, these are cap tube systems so air probably won't create a blockage as it will with float-based units (ie Monitor Tops). It will cause high power consumption, and probably the first 6 inches of the evaporator, starting with the cap tube inlet, will defrost between cycles. Typically being R12 systems, they operate at pressure at all times, in general, so if there is any leak it will likely lose the charge well before it draws in air. 

That is a beautiful restoration, too. Nice job! 
Sincerely,

David 

 

[combo52]

Freezer temperatures in single door refrigerators

Can never consistently reach 0° or even close, if you were able to achieve 0° nearly everything in the refrigerator section would get frozen to some extent.

It would be impossible to keep any type of produce or even a bottle of water in the refrigerator without it freezing.

These early refrigerators weren’t designed to run that cold in the freezer they were designed for holding frozen food that was already frozen even a box of ice cream usually has to be firmly against the floor of the freezer to keep it from melting.

Hopefully you’ll get some good use out of this beautifully restored refrigerator it sounds to me like it’s actually working OK but more testing may be in order.

John L

 

[turbokinetic]

Hi John, I'm pretty sure he was talking about one of my videos where I ran the compressor without thermostat control; with a test thermometer frozen to the shell of the evaporator. I wanted to see the lowest temperature it would reach, as a health check on the system. I haven't re-watched the video but apologies if it let on that the freezer should always be that cold. 

 

[rp2813]

Just to clarify, my '39 Westinghouse would only run for a minute or two at a time.  The periods between run cycles were much longer than that.

 

Also, like both John and David have stated, the evaporator surface temperature may get down to zero or lower, but the actual temperature inside the freezer cavity will be significantly warmer than that.  IIRC my '52 Kelvinator maintains ~ 15 degrees in its freezer.

 

[goatfarmer]

Nice 'fridge, I have a similar one.

 

[italiantuneup]

Thanks for chiming in David! You're right about the source of the gasket, added some relief cuts.

I actually DID think I could run the freezer at 0 in real world use, but not because your video outright suggested it. When I saw 0deg in your vid I conveniently forgot there's only a 20deg or so temp differential in my fridge, like John said (takes two times to sink in)

I checked the sensing tube, it looks reasonable to me, clamped midway between two evap tubes and ending flush with the bottom of the freezer box.

I opened the relay, surfaced the contacts with a points file. They wouldn't be good enough for my car, but I didn't want to remove too much material. After powering the fridge on, it ran for 45 min straight... so that's a lot better. It hovered around 2.1A most of the time, lowest was 1.88A.

The overload circuit tripped twice on the way down to temp. I put a video of it on Youtube (link below).

I took a look at the wiring to see if anything was obviously damaged. I originally didn't rewire because it all looked original (factory loop fittings) and sheathing felt pliable. After touching all the wiring, I couldn't get the YT relay to trip again. Maybe I should just rewire it to be safe.

 

[turbokinetic]

Hi Justin.  That gasket sure looks better now! 

As for the overload tripping, I watched and commented on your video. It looked like the start contact side of the relay was not making contact during the first attempt. The old thermal relays are very hard to refurbish where they work reliably in all ambient temperatures. I would encourage you to replace the relay with a brand-new Supco RO81 relay. This will take the place of the start and overload functions of the original relay. It's about a $10 part and installs by taking the place of the wiring harness between the original relay and the compressor.  The attached diagram shows both the original and then modified connection scheme. The original relay can stay in place and continue to be used as a junction point for the factory wiring.

Here is one online supplier.  I will caution you that certain antique specialists re-package and resell this part for about $40 so don't fall for that ruse. https://www.zoro.com/i/G9889595/ 

 

On a related note, the compressor can never re-start after it has been powered on; until after the thermal relay has fully reset, and the pressures in the system have equalized.  One minute "off" before re-starting is very nearly too short of a time. If the thermostat is re-cycling on after only a one minute off-time, this can cause the compressor to fail to start; and trip the overload. This would be the case with any start relay, modern or original. 

Sincerely,

David

 

Ps - Supco sells several RO series parts. They are rated on compressor normal running current, and sold for specific horsepower machines at specific voltages. They all look the same so be sure to get what is correct for your machine. I have used countless RO81 size units for the 1/8 HP Frigidaire like yours.

From smallest to largest:
RO82 - Very low HP; 115V 1/20HP early Frigidiare and modern mini-fridges 1.66A overload
RO81 - 115V 1/12 HP to 1/5 HP  - majority of domestic single-door fridges without separate freezer 4.05A overload

RO41 - 115V 1/3 to 1/4 HP Full size fridges, with freezer, soft drink coolers, larger fan-cooled units 6.8A overload

 

The above suggestions are "ballpark" ranges and you should always look at actual specifications before choosing a part.

 

 

[italiantuneup]

Ok, I rewired everything between the wall and the relay, left the t-stat and light circuits alone. Added in the Supco RO81 unit using David's diagram.

I also pulled the t-stat out of the body shell a few inches so I can see what it's doing while running. I filled freezer and main compartment with water bottles, let the fridge run overnight at t-stat "position 1" to stabilize. It was at 12F in the freezer this morning.

Today it is cycling every 5m, here's what it looks like:

* Running cycle is 1m 30s, t-stat contact is closed when it starts, 2.1A running draw
* Compressor shuts off, t-stat contact is STILL closed, 0.5A idle draw
* After 15s, Amperage spikes to 10A, old relay buzzes like in my video from earlier, something trips and we drop back to 0.5A
* 3m 30s later, compressor restarts normally, and the process above repeats consistently

From what I'm observing, the t-stat isn't asking for these cycles. It appears to snap into position (binary open/closed, no degrees of contact). It stays closed.

Sometimes: before the compressor shuts off, power will spike to 4A. This causes compressor to stumble slightly and recover. When it finally shuts off, there is no amperage spike.

I'm thinking I may remove the old relay entirely, since it still seems to be operating in some way. Even if it's not affecting anything, it makes unnecessary noise.

So what might cause the compressor to shut down consistently at 1m30s with a closed t-stat?

 

[turbokinetic]

Justin, the problem is the thermostat. It is glitching and breaking the circuit for a fraction of a second, causing the stumble; or causing the stall.  

The 0.5A "idle" draw is very abnormal and makes me think that the canbinet light may not be cutting off. 

 

[italiantuneup]

You're right, I forgot that I have the side panels/covers pulled off, so the light switch isn't in place. There no draw with the t-stat off and the light switch depressed.

Could an intermittent short in the thermostat leads cause this glitch? The contacts aren't perfectly flat so I could file them some more. I assume aftermarket replacements are possible if that's not sacrilege...

 

[italiantuneup]

In for a penny... I've ordered a JC electronic thermostat, similar to what home-brewers use. It will allow me to set the cut in/out temperatures specifically, plus a minimum reset period to prevent short cycling. Probably going to disconnect the OEM relay, stat, probe but leave them in place in case I ever want it stock again. Will update with results...

 

[turbokinetic]

Glad you found the cause of the off-period current draw! 

I bet that aftermarket controller will work well for you.  Just be sure to emulate the factory setup and place the sensor on the evaporator where the original sensing tube is located.  Set the cut-in for about 20°F and the cut-out for about 5°F; with a minimum 300 second off-cycle.

Play with those numbers and see how it does. You don't want the coil defrosting between cycles, so keep the cut-in far enough below 32 so that doesn't happen. Constant defrosting in between each cycle is bad for the evaporator on these since they aren't designed for that.

 

Sincerely,

David