Author Topic: High-humidity problem fixed?  (Read 1870 times)

John@PC

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High-humidity problem fixed?
« on: December 16, 2014, 02:20:42 PM »
This post may be of interest if you have a fridge-sized cave in an unheated environment.  My cave is a 23 cu. ft. fridge in my garage and for the last few weeks temperature in my garage have averaged less than my target aging temperature of 55F, so with the compressor not running the %RH stayed very high.  By the time I figured out what was going on I was getting some off-odors (i.e. the dreaded "refrigerator smell" :() so I put a box of baking soda in the fridge and was ready to switch to my "winter" controller (a 2 stage thermostat that can cool and heat) but then realized that if the garage temperature stayed withing the temperature differential of 2 deg. (which it often does) the compressor would still not cut on.

So I thought what if I put a very small amount of heat in the fridge during the cold months and just kept it on?  I put a small (7W) night-light bulb to see and it seemed to work.  I logged some data (in chart below) that shows before and after the lamp was turned on.

But even though it was only 7W it made the compressor cycle too much when on, so I started thinking about how I could control the heat and add it only when needed.  I realized that if I used my humidity controller to turn on the lamp that may work. I know it's counter-intuitive but when the cave temperature drops humidity will increase, so if humidity target is 85% the lamp would cut on above that, warm the fridge enough to start the compressor and then cut off when %RH drops below setpoint.

I'm out of town helping tend to a sick grand-twin but when I get back I'm going to give it a try and report results. 

qdog1955

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Re: High-humidity problem fixed?
« Reply #1 on: December 16, 2014, 09:17:10 PM »
John---had similar problem---used this controller---for heat and cooling----they have others. http://www.amazon.com/Elitech-All-Purpose-Temperature-Controller-Thermostat/dp/B008KVCPH2/ref=pd_sim_hi_5?ie=UTF8&refRID=1S3C7A1B971VGTP00JGS
Qdog

John@PC

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Re: High-humidity problem fixed?
« Reply #2 on: December 16, 2014, 10:34:28 PM »
We sell a similar (and I think superior  :D) 2-stage controller but it isn't so much a temperature control problem in my case but humidity control.  In my garage in winter the temperature "hovers" close to the target 55F or just below so the fridge just sits there and "accumulates" humidity.  We're in SC so it doesn't get all that cold in my garage; just cold enough for this humidity accumulation to occur.  Again it's counter-intuitive to control the heating cycle with the humidity controller (and I still need to test it) but I was hoping this could be a solution for people who don't have the second heating relay that a 2-stage has, even if they just put a very low-wattage lamp (and I'm talking 5W or less) in their cave and run it all the time.  As far as the fridge is concerned it just thinks it's already summer  8).

qdog1955

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Re: High-humidity problem fixed?
« Reply #3 on: December 17, 2014, 10:50:21 AM »
Now I understand----us people in the great white north don't normally understand 55 degrees in the winter :)
Qdog

John@PC

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Re: High-humidity problem fixed?
« Reply #4 on: December 17, 2014, 01:45:00 PM »
Qdog, I need to back up and agree with you that the STC-1000 2-stage looks like a fine controller with an exceptional price - definitely a good choice for DIY'ers.  Relatedly I came across this little jewel: http://www.amazon.com/Farm-Innovators-TC-3-Thermostatically-Controlled/dp/B0006U2HD2/ref=pd_cp_hi_2 which looks like it could be very useful in the "great white north" or for simple protection from excessive cold or heat. 

qdog1955

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Re: High-humidity problem fixed?
« Reply #5 on: December 17, 2014, 09:41:26 PM »
That might be an easy way to solve some problems.
 You know, John, those Chinese controllers aren't half bad---I've had a couple of them for almost three years----use one on my smoke house---but a warning----the instructions are in classic "Chinglish" and can be hard to follow.
Qdog

John@PC

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Re: High-humidity problem fixed?
« Reply #6 on: December 18, 2014, 11:22:35 PM »
Yes qdog the instructions can be difficult for us to understand as written but I know my friends at Willhi are improving.  We (PC) write our own instruction manuals for our controllers so I hope that helps with the translation situation  :).