Need Help With Keezer Cycle

[gordo_t]

Ok so i need some advice before I start pulling things too far apart.


Little back ground: Built a kegerator out a small 160L freezer (F&P H160 - prob 3to5 years old) that used to be used for fermenting hooked up to a temp controller, as far as i knew it worked fine i.e. when i looked at it was within temp range, and rarely heard it on, not that I looked at it every hour.

Built a collar (50mm spotted gum), adhered to freezer with liquid nails (set for 3 days), thick bead of silicone around the collar seal from the inside, and attached 20mm thick polyurethane foam to inside of collar.

I use and STC1000 with the temp probe in a 345ml empty beer bottle, sitting at the very bottom of the keezer.

Freezer was on over night to cool down, in the morning I thought it was cycling a bit too often and for too long. I noticed half hour cycle, and took an hour before cycling in again. this has only a 1 degree difference, i.e set at 2deg, heats up to 3 deg (takes a an hour) then half hour to cool back down to 2 deg.

Figured i'd give it a few more hours to settle but tonight these are the temps/times i'm now getting; (I turned it off and looked around inside for about 20 mins so it got a bit warmer, though it still had 3 full chilled kegs sitting in it)

19:45 5.5 deg
20:36 4.8 deg
21:05 4.1 deg
21:25 3.4 deg

so in summary it has taken it 1 hour 45 mins to cool 2.1 degrees. I will check it again once it reaches set temp of 2.0 degree, but i'm assuming it will only take an hour to creep back up to 3.0.

I should also add that since this morning, thinking that it could be a seal issue, i put a light in there to make sure i couldn't see anything shining through the seal, and have since also put a few stacks of books on the lid (about 15 - 20 kgs worth) to hold it down tight.


What sort of 'process of elimination' checks could I do before I call this freezer a lemon. I do have another freezer in the garage (now used for fermenting), and another digital thermostat available for testing.

 

[geneabovill]

Try filling the beer bottle the probe is sitting in with water. It's measuring ambient-ish temps which can confuse the controller. If it really is a lemon I'll trade some tallies for it - my brothers a fridgy.

 

[Brewman_]

yeh does not sound right.
Can you hear the compressor running? If yes, then it is probably stuffed, else,

Can you by pass your cdontroller?
Is you controller set to cool or heat?

Fear

 

[Phoney]

Take the kegs out, put some big PET bottles full of water in there, then plug the freezer on bypassing the STC-1000. ie: As though you are running it in normal freezer mode. If the bottles are frozen solid within 12 hours then it is working fine. If they arent freezing up, you've got a problem.

And I second the comment to keep your probe in water, ambient air temp fluctuates way too much.

 

[gordo_t]

Take the kegs out, put some big PET bottles full of water in there, then plug the freezer on bypassing the STC-1000. ie: As though you are running it in normal freezer mode. If the bottles are frozen solid within 12 hours then it is working fine. If they arent freezing up, you've got a problem.

And I second the comment to keep your probe in water, ambient air temp fluctuates way too much.

Ah yes sorry I mislead you guys with the original comment, I should have said the probe is sitting in an old beer bottle that is filled with water (tape over the top to hold it in there) and sitting on the bottom of the freezer. shouldn't have said it was an empty beer bottle.

Good idea about the freezing bottles, i will pull the kegs out and try that today.

 

[gordo_t]

yeh does not sound right.
Can you hear the compressor running? If yes, then it is probably stuffed, else,

Can you by pass your cdontroller?
Is you controller set to cool or heat?

Fear

Yep I can hear the compressor running, so it runs for about 30 mins (cooling from 3deg to 2deg), and over an hour it will rise back up to 3 deg and kick in again.

Definietly set to cool,

I would have thought that since the probe was immersed in water it would remain stable for much longer. haven' had any experience with keezers before, a rise of 1 deg over an hour might not be a big deal so long as it only took the compressor 5 mins or so to cool it back down (rather than in my case at least half an hour).

 

[glenwal]

I would have thought that since the probe was immersed in water it would remain stable for much longer. haven' had any experience with keezers before, a rise of 1 deg over an hour might not be a big deal so long as it only took the compressor 5 mins or so to cool it back down (rather than in my case at least half an hour).

Stable does not just mean it won't rise, it also means it takes longer to cool. If you take the probe out of the bottle does it work any better?

 

[gordo_t]

Stable does not just mean it won't rise, it also means it takes longer to cool. If you take the probe out of the bottle does it work any better?

True, I was just hoping for better times i guess.

I did leave the probe out of the bottle, but didn't measure how long it took the freezer to get down to temp. only how quickly it rose, which was:

17:45 compressor off once reached 2deg (air temp kept dropping down to 0.2)
17:59 compressor back on once air temp reached 3deg

Will have to do another test later to see how long the compressor runs to get down to temp with the probe just hanging.

I moved all of my kegs into my fermenting freezer at the moment, which has no collar, have the same bottle of water with the probe in there. So I will see how that cycles once temps have settled to compare (freezers are the same make and roughly same size/vintage) - how ever it is in a tin shed (insulated) but its a steamer of a day here at the moment.

The freezer with the collar has a 2 soft drink bottles filled with water, and have let the freezer thermostat go by itself to see if it will freeze the bottles by tonight sometime.

 

[gordo_t]

Well I had two bottles in the freezer for 13 hours (9.20am - 10.20pm), prob 2 litres in one bottle and a litre in another.
The freezer ran flat chat the whole time as I guess it was supposed, I wouldn't call the bottles frozen solid but they had frozen most of the way, there was still liquid to be seen moving around but I wasn't able to crush the bottle of ice between by hand. If I had left it another 2 or 3 hours it would have probably been frozen all the way.

Have my kegs all sitting in another freezer, hooked up with the same STC-1000 and same bottle of water sitting on the bottom. I will be able to compare this arvo how long that one kicks in for, and how long it takes to come back up.

 

[cdbrown]

It doesn't sound like it's broken - warms up, compressor starts and cools it down, stops and then slowly warms again. I guess the big issue is the frequency of it turning on. Was it a hot day? External temps of course will affect the internal temp causing it to cycle more often. Not too sure about the length of time it takes for drop temp - guess I should pay more attention to mine.

 

[stux]

Freezer's really don't like running empty. I'd try it with your kegs in there and see how it goes

 

[gordo_t]

Well to conclude, I went and bought one of those power usage meters. cycle times where still the same, half hour on then hour off. turns out it is only using 1kw every 40 hours, so that works out at roughly 219kw per year (that math is done in summer, so consumption should ease off once it gets cooler). Freezer is rated about about 340kw per year or so, which means its running absolutely perfect.

 

[WitWonder]

Freezer's really don't like running empty. I'd try it with your kegs in there and see how it goes

Agree with this comment. Bigger thermal mass = longer cycle times/less fluctuation in temperature.

Well to conclude, I went and bought one of those power usage meters. cycle times where still the same, half hour on then hour off. turns out it is only using 1kw every 40 hours, so that works out at roughly 219kw per year (that math is done in summer, so consumption should ease off once it gets cooler). Freezer is rated about about 340kw per year or so, which means its running absolutely perfect.

Cool (literally). :beer: PS How much was the power meter and where did you get it? One of those could be handy (like, once a year handy...)

 

[gordo_t]

Agree with this comment. Bigger thermal mass = longer cycle times/less fluctuation in temperature.


Cool (literally). :beer: PS How much was the power meter and where did you get it? One of those could be handy (like, once a year handy...)

JAycar was only $20, well worth it as I found out the old household fridge is using 2.4kw per day (it is an old fridge) and has to go.
And proved to other half how very little a fermentation fridge (chest freezer) actually uses even compared to computer or TV.

 

[QldKev]

JAycar was only $20, well worth it as I found out the old household fridge is using 2.4kw per day (it is an old fridge) and has to go.
And proved to other half how very little a fermentation fridge (chest freezer) actually uses even compared to computer or TV.

I did the same, got a meter and started measuring things around the house.

This post summarizes where I got up to. Our computers in our house use most the power <_<

I should get around to measuring the tv's one day. I think the old plasma in my sons room (50 inch) with a full home theatre setup running may be a bad user too.


QldKev