On 2019-01-16 13:15,
trevor.perry508@gmail.com wrote:
On Thursday, 30 August 2007 23:06:23 UTC-4, homebrewdude wrote:
I have a industrial type SS fridge. I think this can either be a
fridge or a freezer, but the thermostat is the limit.
I am currently running a Johnson digital control on it. I would
like to bypass the internal thermostat and have it turn off and on
based on the johnson control.
Can I just jumper the thermostat? Or is this more complex?
I too could use some help here. I recently got a wine/beer cooler RCA
RMIS 2434 is the model number. This cooler has been ok so far cooling
the way it needs to. The problem is the lowest setting is 41 and I'd
like to get the cooler colder for my beverages.
I've read up on a couple things, bypass the thermostat by wiring the
two wires into the thermostat together and also heard of getting a
johnson controller that goes into the wall. I'm curious as to if I
can get some help on what I should do and how I should go about it.
Looking at a picture it seems that your cooler has digital control:
https://images-na.ssl-images-amazon.com/images/I/61wL9hTxOEL._SL1000_.jpg
There are several ways to handle this. One is to find the relay that
turns on the compressor and bridge its contacts from mains to compressor
motor (and coil fan, which is often hooked up in parallel). Now the
cooler compressor would run all the time. You can connect the cooler to
mains via an external controller that has a sensor which goes inside the
cooler and this would cycle the whole thing on and off.
The other way is to hack the innards. Find out where the sensor is,
mostly this will be an NTC or PTC resistor on a cable from the
electronics towards the back. You could fool the unit into a "wrong" temperature by adding a resistor there.
Lastly, you could install another internal thermostat and let that
control the low voltage relay line.
However, be aware of caveats such as these:
1. Going below 41F can cause occasional local ice build-up and the unit
may not have means to deal with that It could potentially become damaged.
2. The external controller must have short-cycle protection. For
example, after a very brief power outage while the compressor was
running it must wait some time before turning it back on. On an older
fridge I am using a Chinese Willhi external controller which has
short-cycle protection. You also need to set a sufficiently high
hysteresis to avoid short-cycling. I set mine to +/-1F.
3. In the summer months the compressor could run flat-out all the time
and barely get it to your desired lower temperature. The compressor
might not be tough enough to withstand such a high duty-cycle use.
This is my fermentation set-up with temp control mods (except now I have stainless fermenters in there):
http://www.analogconsultants.com/ng/brew/Blowoff.JPG
Here is our old Bosch fridge from 1956 in a carbonation setup when it
was way too hot outside:
http://analogconsultants.com/ng/brew/Fridge_1.jpg
Sometimes I use the Bosch to ferment if I run out of space.
--
Regards, Joerg
http://www.analogconsultants.com/
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