Cooling upgrade on refrigerator. If it works, it ain't stupid!

[Th3_uN1Qu3]

I had this refrigerator at my old folks which I noticed I would put my beer or soda in and take it out warmer than I'd brought it from the store.

Now, I don't know much about refrigerators or HVAC but to me it seemed like we have a problem. I threw a thermometer in... 20 deg C in the fridge. WHAT THE... Freezer worked fine with temperatures way below zero, as it should, and it has only one compressor for both sides so it got me scratching my head for a while.

Only other things that seemed a bit odd was that the heatsink on the back was barely warm and the compressor was very, very quiet. Hmm.

I read around for a bit and saw that no frost refrigerators have a fan in the freezer which blows air in the refrigerator compartment. I looked for it, nope. Didn't find one, nor did I find a service manual for this. Just the user manual. However, in the user manual of another model a fan was mentioned, in this one, no, so maybe it doesn't have one.

Last night I went to grab a bite and noticed the compressor louder than usual, the heatsink hot to the touch and *gasp* the fridge was cold inside this time and condensation started forming inside on the rear, as it should. The past couple days had brought colder weather... Hmm.

I remembered that the compressor has a "Thermally protected" label on it. Could they have put a PTC thermistor on it? That would explain everything. YES, they did.

Today the sun was up and I had 20 Celsius in the fridge again. So, without further ranting, my hunch turned out to be correct and I present to you the redneck solution to an overheating compressor. Now my beer is cold again all day long.

[momaka]

Re: Cooling upgrade on refrigerator. If it works, it ain't stupid!


One more reason not to toss out all of those old ATX PSUs.
Wonder how long that solution would last, though. Well, now with autumn/fall and colder temperatures coming, maybe that won't be such an issue soon.

BTW, the REAL redneck way to cool your beer would have been to put it all in the sink and let it sit under slow running water.
Same method was/still is used in these parts of the world for large items like water melon too.

[petehall347]

Re: Cooling upgrade on refrigerator. If it works, it ain't stupid!

i cant figure our what you did

[momaka]

Re: Cooling upgrade on refrigerator. If it works, it ain't stupid!

i cant figure our what you did

It took me a while to see "it" / the "fix" , too ... but I won't spoil it. Just look carefully at the 1st photo.

[petehall347]

Re: Cooling upgrade on refrigerator. If it works, it ain't stupid!

It took me a while to see "it" / the "fix" , too ... but I won't spoil it. Just look carefully at the 1st photo.

ah yes i see it now

[ron350]

Re: Cooling upgrade on refrigerator. If it works, it ain't stupid!

I like that fix.

Is there a reason why compressors don't have aluminum heat sinks glued all over them?

[CapLeaker]

Re: Cooling upgrade on refrigerator. If it works, it ain't stupid!

Sweet fix! Dirt@$$ cheap and effective!

[Th3_uN1Qu3]

Re: Cooling upgrade on refrigerator. If it works, it ain't stupid!

I like that fix.

Is there a reason why compressors don't have aluminum heat sinks glued all over them?

Commercial and outdoor units have a fan bolted on the side of the compressor.

This one is way past its warranty, and there was another problem which probably led to the current situation: the white tray on top of the compressor collects the condensed water from the fridge compartment, which the heat rising from the compressor evaporates. That tray had fallen off and the water had been dripping behind the fridge for a long time.

Now, it's a small amount of water so it wasn't noticed except when I pulled it away from the wall and saw the mess it made. However, I have a hunch that the cold water getting collected in the tray to be evaporated also aided in the cooling of the compressor, and it running for so long without the tray on top made it go out of spec.

There will be more drunken engineering tomorrow, I'm cooking up a replacement temperature probe. It now works reasonably well, but I believe there is a single temp sensor and it's in the freezer, as the temperature variations in the fridge between compressor ON and OFF are quite large. It's still a lot better than having the compressor run all the time and not manage to cool down anything though.

[R_J]

Re: Cooling upgrade on refrigerator. If it works, it ain't stupid!

Check if the compressor uses one of these type of PTC start relay/thermistor They are cheep and easy to replace, usually located under a cover

[stj]

Re: Cooling upgrade on refrigerator. If it works, it ain't stupid!

the white tray on top of the compressor collects the condensed water from the fridge compartment, which the heat rising from the compressor evaporates.

you should put a splash of concentrated disinfectant in that or mold can grow in it.

[sam_sam_sam]

Re: Cooling upgrade on refrigerator. If it works, it ain't stupid!

If it has a coil on the other side of the fan that you put make sure that it is also clean because this can cause the compressor to overheat

[redwire]

Re: Cooling upgrade on refrigerator. If it works, it ain't stupid!

I would check the power consumption with an energy meter.
PZ75E1B compressor is 140-200W apparently and seems to use a PTC start relay.
Fridges are made so cheap, pennies saved. They couldn't give the compressor some fan cooling? I'd power the fan off the switched power.

Mold control is TSP trisodium phosphate, I imagine it also kills bacteria like Legionnella that likes warm wet places air conditioners. If your tray looks scary.
I find the condensor coils are always full of dust.

[Th3_uN1Qu3]

Re: Cooling upgrade on refrigerator. If it works, it ain't stupid!

Check if the compressor uses one of these type of PTC start relay/thermistor They are cheep and easy to replace, usually located under a cover

Thank you. There is a small black box to the left of the compressor, where the power cable goes in and from there the cables split going to the compressor and the control inside the fridge.

I'm going to take it apart and see what's inside.

[stj]

Re: Cooling upgrade on refrigerator. If it works, it ain't stupid!

i dont think anything is inside that box - there wasnt on the last 2 i stripped.

[Th3_uN1Qu3]

Re: Cooling upgrade on refrigerator. If it works, it ain't stupid!

Thanks, saves me some time. Weather has been getting significantly cooler today, and so far, so good. 3 degrees C on the topmost shelf.

Someone else suggested another thing to check, there should be a valve between the freezer and fridge compartments which may be getting stuck closed. That's on my to-do list along with replacing the PTC.

[petehall347]

Re: Cooling upgrade on refrigerator. If it works, it ain't stupid!

wrap your beer in tissue paper and soak with water and put in the freezer for 30 minutes ,,

[Th3_uN1Qu3]

Re: Cooling upgrade on refrigerator. If it works, it ain't stupid!

wrap your beer in tissue paper and soak with water and put in the freezer for 30 minutes ,,

That's what I had been doing until I fixed it.

[momaka]

Re: Cooling upgrade on refrigerator. If it works, it ain't stupid!

Commercial and outdoor units have a fan bolted on the side of the compressor.

Also fridges made for built-in applications that have the heat-exchanging fins on the bottom and a fan on the back, pulling air through those fins and exhausting it out the back. The fan also helps cool the compressor too, like you noted.
^ Common to a lot of older US fridges, including the 30 YO Kenmore at my parents' house.

Now, it's a small amount of water so it wasn't noticed except when I pulled it away from the wall and saw the mess it made. However, I have a hunch that the cold water getting collected in the tray to be evaporated also aided in the cooling of the compressor, and it running for so long without the tray on top made it go out of spec.

Actually, I think the tray on top is not so much for helping to cool the compressor as it is for heat rising from the compressor to help with evaporating the water quicker.

Someone else suggested another thing to check, there should be a valve between the freezer and fridge compartments which may be getting stuck closed. That's on my to-do list along with replacing the PTC.

I thought about suggesting that... but if it was a stuck valve, I don't see how adding the fan could have fixed it / made it work.

Otherwise, valves getting stuck or blower fan between freezer and fridge going bad is not too uncommon, at least for fridges that take cold air from the freezer and pipe it into the fridge. In fact, my sister's fridge developed that fault (stuck valve) last year... except the valve got stuck open instead of closed, and the fridge was basically a 2nd freezer. Fridge was a Bosch and not even 3 years old when this happened. Goes to show the quality of modern stuff. Didn't help that Bosch used a specialty-made stepper motor that wasn't available anywhere. Since it was one of those built-in kitchen fridges (with the cabinets) and not a very standard size either, my sis wasn't eager to replace it. The repair took over 3 months (close to 4), since the guy that was repairing it couldn't get a replacement stepper motor anywhere with the listed specs and had to custom-order it. Not only that, but he had to custom-order a bunch of them, due to factory MOQ... and they dude only had a small repair shop, so he wasn't eager to do that either. But then he eventually ran into a number of other customers with fridges with the same fault and same stepper motor failed, so after a few months of waiting, he finally ordered a bunch of these custom stepper motors and got the fridge running.

... and then people ask me why I don't want to switch over my 30 Y.O. appliances to these newer shiny & "much more efficient / green" stainless steel appliances. Yeah, no thanks, but I rather keep my old, ozone/climate-"unfriendly" R12 fridge going as long as it can.

[eccerr0r]

Re: Cooling upgrade on refrigerator. If it works, it ain't stupid!

"ozone unfriendly R12" is a misnomer, as long as it works (meaning it's not leaking) it's not unfriendly.
It's unfriendly if it stops working and you need to recharge...

Reminds me about that other thread I posted, curious how often refrigerant leaks and compressor failures (and anything else that would require discharging of refrigerant to repair) -- I'd be happy to work around thermostat failures!

[momaka]

Re: Cooling upgrade on refrigerator. If it works, it ain't stupid!

"ozone unfriendly R12" is a misnomer, as long as it works (meaning it's not leaking) it's not unfriendly.
It's unfriendly if it stops working and you need to recharge...

Exactly!

In the 30 years we've had that fridge, it's never needed a repair. Well, the door switch for the light bulb went out some 20 years ago and it didn't seem easy to take apart, so I've dealt with it without a lightbulb for 20 years... but no biggie. I know what (food) I put in my refrigerator at all times and where, so I don't need a light bulb at all.

curious how often refrigerant leaks and compressor failures (and anything else that would require discharging of refrigerant to repair)

From what I've seen from regular browsing though Craigslist in the last 10 years, I've seen quite a few fridges given out for free due to being diagnosed with a bad compressor or low on refrigerant (though also a lot of good working ones too, but just too old and/or dirty.) The broken ones tend to fall either in the very new category ("high-efficiency" fridges running at high pressures for their "eco-friendly" refrigerants) or very old category (like my fridge, but never cleaned or maintained or likely abused, and thus more of a compressor failure at their age.) Of course, there are also quite a few in between these two categories too. But the ones that are regularly low on refrigerant tend to be newer (under 10 YO) fridges.