Need help diagnosing/fixing freezer that is not cooling

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eric19312

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Hoping for suggestions for diagnosing issue with stand up freezer. Pretty new unit - maybe 2 years old now, I use it as temperature control for my conical. Tried brewing with S04 recently and went out of town day after pitching yeast. I was pushing the limits on capacity, so had a blow off tube into bucket in the freezer fully expecting some krausen to get pushed over into the bucket. Came back 4 days later and the fermentation had gone quite aggressive, had overflowed my blow off bucket and then filled a sheet pan I keep under the conical inside the freezer (to aid cleanup). I guess the krausen over flowed that pan too as I found it filled the bucket under the freezer (bucket clips to the back of the compressor) was filled with yeast - nasty vinegar smelling semi cooked yeast at that. (story here is a bit out of order, i found the yeast in that bucket later but am thinking this overflow may be linked to my issue)

Anyway fermentation was done, I capped the blow off, switched to gas manifold, let it rest a couple more days and proceeded with yeast dumping followed by dry hopping. Everything was going ok till I went to cold crash and while freezer came right on, a couple hours later still running but no cooling had happened...

Next day started in on watching YouTube videos to try to get this sorted out. Here is my situation...
Thermostat control works and has continuity
Fan works and runs when the thermostat is calling for cold
Fins and coils inside the unit (behind the false back wall) look to be in good shape...not dirty, not visibly damaged
Compressor is warm/hot to touch...not so hot I can't touch it for extended period but warmer than body heat
Checked capacitor...got a multimeter with capacitor testing, capacitory is rated 15 nf +/- 5% and got a 13.25 so I replaced the capacitor. New one checked out at 14.95 nf so installed that...no joy
Checked resistance on the three pins on the compressor...configuration is 1 on top, 2 on bottom, resistance between the 2 on the bottom is about 10, resistance between the top and each of the bottom pins is about 5. [Didn't check pins to ground yet...read about that test last night after I was done for the evening]
Checked the start relay...little foggy on what I did here but remember it involved jumping the electrical connections together and then checking continuity...found a YouTube that walked me through it on what appeared to be exactly my unit and ended up convinced it was good.

So any ideas? Pretty bummed as I've already lost one brew day over this.
 

micraftbeer

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We lost power one year and beer fridge was affected. I got humidity inside that coated the cooling fins inside. So much that the auto defrost couldn't handle it. Slowly got worse and worse for temperature until I was ready to toss it.

I opened it up, took everything out, then used a hair dryer to melt off all the ice on the cooling fins. Let fan blue in there for like 12 hours to fully air it out. Put it back together, works great.

Your overflow could've saturated inside with humidity and got the same frozen phenomena.
 
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eric19312

eric19312

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We lost power one year and beer fridge was affected. I got humidity inside that coated the cooling fins inside. So much that the auto defrost couldn't handle it. Slowly got worse and worse for temperature until I was ready to toss it.

I opened it up, took everything out, then used a hair dryer to melt off all the ice on the cooling fins. Let fan blue in there for like 12 hours to fully air it out. Put it back together, works great.

Your overflow could've saturated inside with humidity and got the same frozen phenomena.
thanks didn't see any ice on the fins. But maybe running a fan with a bucket of damp rid and a heater for a few days is worth trying.
 

Beholder

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Looks like you’ve eliminated electrical and seized compressor. Only additional thing I can suggest is refrigerant leak, but these units don’t have taps that you can check the cycle pressures.

You can install a bullet valve to check pressure and potentially top up with refrigerant or stop leak, but my experience is that these are stop gaps that got me an extra year or two, but of course weren’t permanent.
 

dtashmore547

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I presume you can feel your compressor running else the cutout would operate after a few seconds, if the compressor is running and the condenser is not getting warm and the high pressure pipe from the compressor is not getting hot then you have lost refrigerant, most units don't come with charging ports and to get it going you would have to fit one and charge it to 6psi. done a few myself and the equipment can be purchased quite cheaply but some knowledge is required unless you know someone.
 

Mr. Vern

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Without gauges... You might get a better idea by taking an amp draw on your compressor when trying to start. The relay is a Start/Run circuit using the capacitor to the start pin, and then settles into a closed run status on the adjacent pin (the three pins of the compressor are start-run-common). resistance between the start and run pins will be higher than using the common.

Compare the amp draw to the motor nameplate, if RLA (Run Load Amp) is 5A then you should be close. Starting amps will spike then settle into the running amperage. Load / No Load conditions will affect amp draw slightly, but nothing major.

If you register less than 20% of full nameplate amps you may have a damaged pump/compressor. But given your explanation and scenario I am curious if that caused trouble or simply a coincidence. (keep in mind your fan motor will add a few watts, probably close to 0.05 AMPS @ 110V by itself.

Your compressor should also have a thermal overload, automatically resetting. These are typically 1-2 wire switches that interrupt power to the compressor, and they are going to be touching the compressor wall because it is a thermal safety. These can go bad (fail open) when they are cycling, and they will allow the fan to continue running. (image below is a thermal overload from a Tecumseh compressor). TEMPORARILY you can bypass the switch or disconnect it and check resistance. OPEN is bad. These are located in between the relay and compressor pins... one wire from the Thermal Overload likely connects to the compressor directly.

If you register full amps and no cooling you are low or out of gas, turn off ASAP or the compressor can fail permanently.
overload.jpg
 

SanPancho

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Hoping for suggestions for diagnosing issue with stand up freezer. Pretty new unit - maybe 2 years old now, I use it as temperature control for my conical. Tried brewing with S04 recently and went out of town day after pitching yeast. I was pushing the limits on capacity, so had a blow off tube into bucket in the freezer fully expecting some krausen to get pushed over into the bucket. Came back 4 days later and the fermentation had gone quite aggressive, had overflowed my blow off bucket and then filled a sheet pan I keep under the conical inside the freezer (to aid cleanup). I guess the krausen over flowed that pan too as I found it filled the bucket under the freezer (bucket clips to the back of the compressor) was filled with yeast - nasty vinegar smelling semi cooked yeast at that. (story here is a bit out of order, i found the yeast in that bucket later but am thinking this overflow may be linked to my issue)

Anyway fermentation was done, I capped the blow off, switched to gas manifold, let it rest a couple more days and proceeded with yeast dumping followed by dry hopping. Everything was going ok till I went to cold crash and while freezer came right on, a couple hours later still running but no cooling had happened...

Next day started in on watching YouTube videos to try to get this sorted out. Here is my situation...
Thermostat control works and has continuity
Fan works and runs when the thermostat is calling for cold
Fins and coils inside the unit (behind the false back wall) look to be in good shape...not dirty, not visibly damaged
Compressor is warm/hot to touch...not so hot I can't touch it for extended period but warmer than body heat
Checked capacitor...got a multimeter with capacitor testing, capacitory is rated 15 nf +/- 5% and got a 13.25 so I replaced the capacitor. New one checked out at 14.95 nf so installed that...no joy
Checked resistance on the three pins on the compressor...configuration is 1 on top, 2 on bottom, resistance between the 2 on the bottom is about 10, resistance between the top and each of the bottom pins is about 5. [Didn't check pins to ground yet...read about that test last night after I was done for the evening]
Checked the start relay...little foggy on what I did here but remember it involved jumping the electrical connections together and then checking continuity...found a YouTube that walked me through it on what appeared to be exactly my unit and ended up convinced it was good.

So any ideas? Pretty bummed as I've already lost one brew day over this.
i'd wager its a bad expansion valve.

you didnt say it, but i can only assume the evap is not getting cold. otherwise fan would be blowing air that is cold.

it starts up, the compressor runs, the fans blow...... all you're missing is cold. no evaporation, no cold.

although on the same note- no refrigerant, no cold.
 

Mr. Vern

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Have you tried giving it a good hard bang on the side?
believe it or not, the piston in the compressor can get a little tight after a shutdown. A whack on the side of the pump might just get it going. More hopeful than anything at that point, but it has worked on a rare occasion. If the piston was siezed they will have high amp draw when trying to start (LRA - Locked Rotor Amps). The Thermal Overload may very well activate under these conditions.

bad expansion valve.
A lot of these commercial fridges only have a capillary tube in place of an expansion valve. No seals to fail, ambient conditions are very stable for indoor use, no hot-gas bypass... they can get away without using a valve quite easily. EDIT to add that the freezer was cool 2 days prior.
 
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eric19312

eric19312

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believe it or not, the piston in the compressor can get a little tight after a shutdown. A whack on the side of the pump might just get it going. More hopeful than anything at that point, but it has worked on a rare occasion. If the piston was siezed they will have high amp draw when trying to start (LRA - Locked Rotor Amps). The Thermal Overload may very well activate under these conditions.


A lot of these commercial fridges only have a capillary tube in place of an expansion valve. No seals to fail, ambient conditions are very stable for indoor use, no hot-gas bypass... they can get away without using a valve quite easily. EDIT to add that the freezer was cool 2 days prior.
I’m all for whacking this thing with a hammer at this point. What pump would I be aiming at? The compressor?
 

Beholder

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And everyone more or less in agreement low/no refrigerant is not really fixable?
Fixing is worth a shot, but depends on the refrigerant. If it’s R-134a, install a bullet piercing valve (clamps around the tubing, so no brazing needed), which would allow you to check the pressure.

If it has lost refrigerant, the leak is usually inaccessible, but putting in some $10 stop leak is worth a shot.
 

day_trippr

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One can resurrect a unit and keep it alive until a replacement is ready...


Cheers!
 

Homebrew Harry

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I’m all for whacking this thing with a hammer at this point. What pump would I be aiming at? The compressor?
My Grandma had a very old fridge at a lake house. Every spring when she got there for the season, she had to give the compressor a little bop with a hammer. It would then work all season. Once when I had moved I had a similar problem. I was on the way to smack the compressor with a hammer when it came on... I guess it saw me coming.
 

bracconiere

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for some reason, i'd think if the compressor isn't too hot touch try unpluging it for a couple days....

maybe three at that, then plug it back in.....
 

Mark3885

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Fixing is worth a shot, but depends on the refrigerant. If it’s R-134a, install a bullet piercing valve (clamps around the tubing, so no brazing needed), which would allow you to check the pressure.

If it has lost refrigerant, the leak is usually inaccessible, but putting in some $10 stop leak is worth a shot.
I’ve recharged many small and large freezers and refrigerators . Some work for months, some for days. 2 yrs ago , I recharged a full size fridge at my cabin , it is so cold that I have to keep turning the thermostat warmer. What keeps an old fridge or freezer running is always keep it running, my small keezers are set at a min of 64 F when not being used for fermentation, after a while the oil drains down and the compressor doesn’t have enough to get it going . Hitting it with a hammer sometimes gets it going .
 
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eric19312

eric19312

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so an update

went on a short vacation, left the freezer unplugged. Turned it on when I got back 4 days later and whacked the compressor with a hammer. Was hopeful as compressor seemed to be making a buzzing noise I did not remember from before and seemed like one of the copper lines running from the compressor was getting cold. But still no joy. 12 hours later freezer temp has not budged.

So investigating the coolant recharging options suggested by @day_trippr

Read you thread, seems that you were needing to recharge about monthly? Did you ever try a stop leak product?
 

day_trippr

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I think near the end it was down to a couple of weeks between top-ups, which averaged ~30 grams.
I did not try any stop leak product, and now that you mention it I wish I had tried that on the old machine once the new one was up and serving, just to see what might happen...

Cheers!
 

Dr_Jeff

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the leak stop is usually in with the freon charge, I'd give it a try and hope for the best, and if it didn't work, I'd know for sure that it was a lost cause

my guess it, that it would be under $20 to find out for sure
 
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