Is it ok to have controller probe immersed in water?

[J2W2]

Hi,

I'm using a Johnson A419 controller in my keezer. Initially I had used Velcro to attach the probe to one of the kegs; I'd also covered the probe with a piece of neoprene. I noticed the keezer was still cycling fairly often, and for pretty short periods of time. I'm guessing that even when it's full of beer, the outside of a keg probably changes temperature fairly quickly, because of the amount of surface area exposed to the air in the keezer.

So I took a 16oz plastic bottle and drilled a hole in the cap, just large enough for the probe to fit through. I filled the bottle with some diluted Star San (probably about 25% of normal strength), put the probe in the bottle, and sealed the gap on the cap with some paraffin wax.

The way it's setup, the probe and probably 2" of the connector wire are in the Star San solution right now. I'm wondering if that will eventually harm the probe in anyway? I believe the end of the probe is either aluminum or stainless steel. The probe is crimped at the top, around the wire, but I don't know if that forms a water-tight seal or not.

Do you think it's ok to leave the probe immersed like that, or should I try to move it up in the bottle so that a little of the top of the probe, and all of the wire, is above the liquid?

Changing my setup like this has really altered my keezer cycles. Since it's now based on a temperature change in 16oz of water, it cycles on much less frequently, and runs for longer periods when it does. I assume it is better on the compressor and the freezer in general to have it run this way, rather than having it kick on frequently for a lot of short cooling cycles.

Thanks for your help!

 

[broadbill]

I wouldn't trust that probe to be waterproof unless they manufacturer specifies that it is. The fact that you say it has a crimped top tells me that is almost certainly NOT waterproof. I am unaware that way of the popular temp controllers have a waterproof probe.

I'll keep my fingers crossed that yours is ok...I would recommend a different setup...I like the bubble-wrap-taped-to-the-fermenter approach. Works great.

 

[dyennie]

I've had mine in a white labs yeast vial filled with mineral spirits for about three years with no issues. I didn't go with water since it evaporates.

 

[J2W2]

I re-did mine so only the probe is in the water. The crimp is now just outside the cap. The probe just fits through the hole, and I have some paraffin around it so I think there should be little to no evaporation.

It definitely cycles the freezer differently. What's the best way to check beer temp? My laser sensor doesn't work well on a glass - I suppose an immersion thermometer?

Thanks for your help!

 

[RocketBrewer]

Might be safer to fill the bottle with some fine sand.

 

[ajdelange]

My laser sensor doesn't work well on a glass - I suppose an immersion thermometer?

To make your 'laser sensor' work stick a piece of electricians tape on the glass. Just be sure the thermometers lens is directed at the tape i.e. allow for any parallax between the lens axis and the laser beam

 

[J2W2]

To make your 'laser sensor' work stick a piece of electricians tape on the glass. Just be sure the thermometers lens is directed at the tape i.e. allow for any parallax between the lens axis and the laser beam

Thanks, I'll have to give that a try. I have an immersion thermometer as well, but it's way easier to hit it with the laser, and no clean-up.

 

[drgonzo2k2]

The probe for my Johnson A419 has been sitting in a 22 oz bottle filled with 90% distilled water and 10% rubbing alcohol for about 4 years now with no problem whatsoever. It actually never even occurred to me to check if it was waterproof or not before doing so. It's been keeping my beer "cellar fridge" at a constant 53 degrees that entire time, so I'm either extremely lucky, or they are waterproof.

YMMV of course, so if you're really worried about it I'd try to contact the manufacturer just to be safe.

 

[colorolo]

Just a question, why fill with star san? Who cares if it's sanitized?

 

[rodd]

Just a question, why fill with star san? Who cares if it's sanitized?

I don't want it to be a source of life in my keezer.

 

[AnOldUR]

Might be safer to fill the bottle with some fine sand.

I put my temperature probe in a box of baking soda. Along with keeping the compressor from cycling as often, it has the added benefit of odor control.

 

[broadbill]

I'm curious: why do people go with the small liquid filled container instead of taping the probe directly to a fermenter? To me, the latter methods seems like such a no-brainer in terms of ease, accuracy and will limit possible damage to the probe.

Thanks!

 

[colorolo]

I don't want it to be a source of life in my keezer.

Point taken. I'll be replacing my water this evening!

 

[AnOldUR]

I'm curious: why do people go with the small liquid filled container instead of taping the probe directly to a fermenter?

Original Post:

I'm using a Johnson A419 controller in my keezer.

 

[BrotherBock]

To make your 'laser sensor' work stick a piece of electricians tape on the glass.

+1

I did a test with my 6.5 gallon glass carboy. I've taped the probe to the glass, put it in the thermowell, and cross checked it with my sticker thermometer. All said the same temp.

So don't be afraid to just tape it to the glass. And this test showed me that those sticker thermometer are very accurate to the temp in the middle of the carboy. Which makes sense if you think that even during vigorous fermentation everything is churning and moving around, so why wouldn't the temp be distributed evenly?

 

[broadbill]

Original Post:

OK then Mr. literal...same question....why not just tape to a keg?

 

[BetterSense]

Because you have to undo and redo iit every time you change kegs. Plus the keg has different amounts of beer in it all the time possibly even empty.

 

[AnOldUR]

OK then Mr. literal...same question....why not just tape to a keg?

Which one? My kegs don't last that long and rotate out.

So much easier to use something that stays in there all the time.

A fermentation chamber is a completely different situation.

Cheers!
Mr. Literal

 

[BrotherBock]

Because you have to undo and redo iit every time you change kegs. Plus the keg has different amounts of beer in it all the time possibly even empty.

Tape it to the bottom?

 

[doug293cz]

If you tape a probe to a warm keg and put it in the cooler, the compressor will run until the beer temp reaches the setpoint, and the chamber will likely be way below freezing. Your beer will then cool lower than your setpoint. There is no active, exothermic process going on in a keg cooler, so no need to go to extra effort to keep the beer from overheating. The beer can't spontaneously heat up or cool down beyond the chamber temp, so controlling chamber temp is all you need to do. You can either use a free hanging temp probe (just make sure you have a long compressor delay to minimize cycling), or embed the probe in a thermal mass to slow down the cycling rate. Both work. Do whichever you are more comfortable with.

Fermentation chambers are completely different. Fermentation is an exothermic process, and the beer will overheat by itself. This is when you want to have the probe measuring the actual beer temp, in order to keep it from getting too warm. With typical fermentation temps, it is unlikely that the chamber would ever undershoot to the point of freezing.

Brew on

 

[DC_0602]

So putting your probe in a box of baking soda works for you all?

 

[doug293cz]

So putting your probe in a box of baking soda works for you all?

Nothing wrong with doing that. Just one of many possibilities.

Brew on

 

[J2W2]

I'm curious: why do people go with the small liquid filled container instead of taping the probe directly to a fermenter? To me, the latter methods seems like such a no-brainer in terms of ease, accuracy and will limit possible damage to the probe.

Thanks!

I initially had the probe held to the side of one of my kegs. I had covered the probe with a piece of neoprene, and used two Velcro straps to hold it on. That was easy to do, and the Velcro was easy to take on and off, and there was no issue with getting tape to stick to a keg.

However, I found that my keezer was cycling on and off more than I thought it should. Metal is a great conductor, so I'm guessing as the air in the keezer warmed up, the metal was probably slightly warmer than the beer inside it. Since I'm cycling my controller on at 41 and off at 39, it doesn't take much change to kick it on. Now that I have most of the sensor (1/2" below the crimp or so) in liquid, my keezer cycles much less often, staying on for a longer period when it does kick on.

 

[aaronmq]

That is assuming that longer, less frequent cycles are better for the keezer than than shorter, more frequent cycles. Can anyone chime in on what they think is better for the keezer?

 

[Stealthcruiser]

Any thermal cycling you can prevent, will prolong the life, of all things mechanical.
Light bulbs, home heating systems, vehicles, jet engines, etc.......

 

[aaronmq]

Yes, but assuming the run time is the same for short, more frequent cycles and longer, less frequent cycles, is there a difference?

 

[ajdelange]

Starting is very much more stressing to a motor than running. Therefore, if you need 10 hrs of running it is better to start once and run 10 hrs continuously than to start and run for half an hour 20 times. From the refrigeration point of view it is better to have the compressor run continuously (control temperature by evaporator by pass) than to have the compressor cycle on and off to hold temperature.

 

[aaronmq]

Perfect, thanks for the clarification!