-80 freezers

[Jeswin]

My boss bought a $3000 Revco -80C freezer at a go-dove auction. Well,
the thing only goes to -35C. I guess the compressor is broken. It
looks pretty clean in the components area. Could a bad seal cause
this? I doubt it.

We need a -80 pretty soon. What other auction sites are there? It's a
pretty big gamble. Order a -80 and you end up with a -20C freezer.

[Steven Stowell]

Looks like there's lots of listings on Labx.
http://www.labx.com/v2/adsearch/resultsnew.cfm?sw=-80%20freezer&te=cat

  Suggest asking for a guarantee, or a photo demonstration of a thermometer/ thermocouple reading while unit is running.

The most amazing deals come from bundled purchases (buy with other stuff) from someone going out of business.  This can be hard to find;  they frequently involve an equipment broker.  Be fearless in your approach of these brokers.  You might get an amazing deal.

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[Dakota Hamill]

Pfizer is shutting down their Connecticut Plant which had almost 2,000 employees, as well as some others in MA.  Dovebid is listing them all, thousands of lots...amazing stuff, but brokers with a heck of a lot of cash make finding really good deals hard.

[Michael Folsom]

Where are you located?  If in CA look at:http://www.hgpauction.com/

[Josh Perfetto]

Very interesting, I also just got a Revco -86C at auction. It worked fine for a week reaching and then holding at -80. Then the temp raised to -30C. After power cycling the temperature again started dropping reaching -60 before failing again and coming up to -30.

I am surprised it failed in this way; I expected it to be broken from the start or work for longer than a week. Maybe just an unlucky coincidence. I am also surprised that power cycling temporarily fixes it, anyone know why that might be?

I am not sure how it works, but during the time it was operating properly it sounded like there may be two compressors, so perhaps the problem is that only one stage has failed. Let us know if you find anything; I want to find a way to fix mine.

-Josh

[Nathan McCorkle]

On Wed, Mar 6, 2013 at 5:15 PM, Josh Perfetto <jo...@snowrise.com> wrote:
> Very interesting, I also just got a Revco -86C at auction. It worked fine
> for a week reaching and then holding at -80. Then the temp raised to -30C.
> After power cycling the temperature again started dropping reaching -60
> before failing again and coming up to -30.
>
> I am surprised it failed in this way; I expected it to be broken from the
> start or work for longer than a week. Maybe just an unlucky coincidence. I
> am also surprised that power cycling temporarily fixes it, anyone know why
> that might be?

how long does it run, how long do you unplug it for? maybe something
is overheating somewhere? oil leaked out (evaporated) or all gummed up
somewhere?

--
-Nathan

[John Griessen]

On 03/06/2013 04:45 PM, Jeswin wrote:
> -80C freezer at a go-dove auction. Well,
> the thing only goes to -35C. I guess the compressor is broken.

Those have a cascade of compressors -- 3 maybe.


On 03/06/2013 07:15 PM, Josh Perfetto wrote:> I am also surprised that power cycling temporarily fixes it, anyone know why that
might be?


Sounds like the heat transfer between stages is messed up. If it stops after going a while,
maybe a stage has water condensation freezing stopping it. Could be bad insulation,
could be the aftermath of a repair with not so good insulation replacement.

[jlund256]

My experience is that the compressors in -80C freezers last 5-10 years.  -80C freezers are expensive to buy, and expensive to keep running.  And they inevitably fail, so you need two, and a plan for where to move things on the day the alarm starts beeping.

There's no easy DIY alternative.  Things generally keep in -20C freezers, just not as long.  To help things keep, seal them in boxes to prevent evaporation, and add thermal mass to the freezer to minimize temperature changes as the freezer cycles.  Items in active use should be fine in a -20C.

Jim Lund

[Josh Perfetto]

I just turn the key to off for a few seconds (some fan keeps running during this time but the compressors stop). Then back on, and it resumes cooling beyond -30. Makes me think it is a control problem of some sort, but no warning lights come on other than the temperature alarm.

-Josh

[Mega]

Depending on your electrical skills you could hack it if it is a failure of the control chip.

Lm335 would be easy to work with, but works only until -20°C IIRC...

you said after switching it on it goes deeper than -30°C.... how about a time switch that switches it off and on again every 20 minutes?

[David Murphy]

I was under the impression that it was a bad idea to power cycle freezers for the same reason you have to leave them sit for a while after transport.

 

(coolent in the wrong place possibly causing damage to the compressors etc.)

I know  the consumer grade normal freezers instructions say to leave them off for at least 10 minutes after they're unplugged if they're unplugged.  

 

 

 

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[Eugen Leitl]

On Wed, Mar 06, 2013 at 07:12:00PM -0500, Dakota Hamill wrote:
> Pfizer is shutting down their Connecticut Plant which had almost 2,000

There's a decline somewhat mirroring the fall of former Soviet Union,
where good pickings could be made. There is a big death in pharma
going on on top of that, so if you hunt for used/surplus times are
good.

Make sure to buy and store for future use, this wave will be over eventually.

[Josh Perfetto]

Just an update on this, I left it off for 24 hours after seeing David say you had to leave these off a bit after transport to let the coolant settle (I hadn't done this (powered it up the minute it arrived) and my manual didn't say to but figured I'd try). I then turned it back on and it's been holding -80 for 5 days straight. However after this earlier episode I'm not going to trust it with any contents unless it holds the temp for another 2 weeks or so :)

-Josh

[Forrest Flanagan]

That freezer probably only has two cascade compressors, like the ones I got at auction for 50 apiece. Once compressor set has a flourocarbon, which stacks with a second set, probably running CO2. If you were in the houston area, I'd point you to a cancer center auction ending in about 24 hours.

In the meantime, there should be a pressure relief on the freezer. Get some dry ice. The twin Puffer Hubbard units I got had a backup that would circulate liquid CO2 from a tank and regulator set.

http://www.slapsale.com/item_desc.aspx?itemid=64336

I got to inspect this set yesterday, they don't look bad and they are labeled down to the -80s. I'd have snapped some pics of the model number if I knew there was interest, I was just there looking at some linear accelerator parts.

Where are you exactly? I've got the time to truck them if it's not terribly far, and the auction house I linked allows anyone out of texas state to buy medical surplus, they just have to register with an out of state address. It's an interstate commerce thing that lets you dodge a medical salvage license.

If you miss that auction, there's some other places off-site for me with lots of freezers. I haven't inspected them, but the place hasn't sold me anything I've regretted yet.

http://www.slapsale.com/item_desc.aspx?itemid=65012

http://www.slapsale.com/item_desc.aspx?itemid=65016

http://www.slapsale.com/item_desc.aspx?itemid=64794

~ Forrest

[Dakota Hamill]

wow slapsale looks like it has great deals if you're around Texas.

http://www.go-dove.com/en/exchanges/BioPharma

Pfizer is closing/moving some plants and a lot of stuff is being sold around New England + Europe

[Josh Perfetto]

I'm in the SF Bay area but also got mine fairly cheap when a local biotech folded (though not $50 cheap, that's incredible). What are you saying about the pressure relief? There is one, do you think it may be the problem? Mine is rated to -86C but doesn't have the CO2 backup system. Still going strong today..

It is good to know for anyone wanting these that they can be had cheaply. I have yet to see the change in the electricity bill though :)

-Josh