DIY Glycol help.

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Ridenour64

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Sooo I came across an old air conditioner that was given to me for free. From the videos I’ve watched and threads I’ve read, seems pretty simple/ basic. I have the shell off and I took the rear fan blade off, but other than that, I haven’t done anything else. I plugged it in just to see if the coils would cool. After a few minutes of being plugged in thought the coils were getting warmer, not colder. It is the rear of the unit that is supposed to cool, right? That fact that I even need to ask that probably means I shouldn’t be doing this [emoji23]
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Ridenour64

Ridenour64

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Man, I was hoping it was the rear because that was positioned perfect to drop into a cooler. Thanks for the quick response.
 
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Ridenour64

Ridenour64

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There isn’t much to cut there. This thing is ancient so it’s probably different than most today. Also, this copper probe, which I assume is a thermometer. Do I splice that pink and purple wire together to bypass the thermometer? Then I can remove the copper thermometer and the electrical component it runs to?
 

Dland

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If you intend to run it from an external controller, you do not need any of low volt circuitry or sensor.

You do need to leave capacitor in place and wired to compressor and fan motor.
 
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Ridenour64

Ridenour64

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I am using an external inkbird.
 
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Ridenour64

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So to be clear, I remove this copper probe, and then splice the pink and purple wires together?
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Bobby_M

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Take the whole squirrel cage fan out of there and the surrounding shroud. The cooler will have to nest right up in there so that the up and over bend of copper can go over the wall of the cooler.

Controls: remove the pink wire off the connection to the black box. Remove the purple wire and move it to where the pink wire was connected. That bypasses the thermostat so whenever the inkbird turns power one to the AC, the compressor and fan will both run.
 
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Ridenour64

Ridenour64

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Thanks Bobby. I wish I wouldn’t have ripped apart the back portion. This would have looked a lot neater.
 

501irishred

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Do you still have the shroud that went around the fan and condensing coil (back half)? You will want it (or something like it if it’s no longer usable). That’s what helps the fan draw air across the entire surface of the coil.
 
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Ridenour64

Ridenour64

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It is no longer in a useable condition. Is it a fire hazard without it?
 

Dland

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No fire hazard, just make sure all your wires are taped off when your done. I was unable to use the shroud on mine and it works fine.
 

501irishred

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I agree that there isn’t a fire hazard, and if it is operated in reasonably cool ambient condition you can probably get away with it. The issue is the internal pressures in the system, the head pressure in particular. As ambient temps rise or amount of air across the condensing coil is reduce, the internal head pressure increases. This is normal and perfectly acceptable to a point but will reduce efficiency, capacity, and compressor life if excessive (without ability to put gauges on it, it’s a guessing game). In short, you might “get by with it”, but why would you? You can make a shroud easily out of a variety of materials, so long as it helps capture and distribute air.
 
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Ridenour64

Ridenour64

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This is a super old air conditioner that I got because I figured I may mess up and I wouldn’t care because I got it free. The reason the shroud won’t fit is because the back piping/ fan is all out of its original setting, and the fan rubs against the shroud. The shroud is also cut. I feel like there is more risk in trying to use it and have it rub, vs not. It’s going to be kept in my basement which at its warmest is mid 70’s. I can’t see an easy way to make a shroud for this based on its design, and if it fails early, I won’t sweat it. As long as it’s safe for my house, I’ll try it as is.

I’m sure this question has been answered before, but I couldn’t find it via my searches. Can I use RV coolant for this instead of food grade PG. RV coolant is around $2 compared to food grade being $25.
 

501irishred

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With few exceptions, distilled water is plenty. Assuming you have adequate flow/exchange across the evaporator coil, nothing “should” be in danger of freezing."
 

Vale71

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I’m sure this question has been answered before, but I couldn’t find it via my searches. Can I use RV coolant for this instead of food grade PG. RV coolant is around $2 compared to food grade being $25.
If your life (and the life of anyone who might be enjoying a few of your beers with you) is worth as little as $23 to you than yes, by all means, otherwise just forget it.
 

Bobby_M

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With few exceptions, distilled water is plenty. Assuming you have adequate flow/exchange across the evaporator coil, nothing “should” be in danger of freezing."
If cold crashing the FV is in the plans, the glycol will need to be in the 26 to 28F area and that means even colder at the coil. No way water will do it.
 

501irishred

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If your life (and the life of anyone who might be enjoying a few of your beers with you) is worth as little as $23 to you than yes, by all means, otherwise just forget it.
RV antifreeze is non toxic and is formulated for use in potable water systems. The biggest working difference is going to be dilution strength. You need much less full strength Propylene Glycol to achieve freeze protection.
 
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Ridenour64

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I will be crashing so I know water isn’t going to cut it. I’m going with RV antifreeze. It is non toxic. Not the same as food grade, but non toxic. There won’t be any possibility of contamination with my beer anyways.
 

Jag75

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How much is rv antifreeze ? If theres no chance of being an issue why doesnt everyone use it instead of the propylene? It cost me 90$ for 3 gallons of that stuff.
 
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Ridenour64

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I bought mine for $2.50/ gallon. It’s not pure. It’s a mix of PG ethanol and water.

I’ve looked for possible cons of using it and all that I could find is that the mix is not at stable as the other stuff and that some people had problems with their mix becoming slush. I only plan on taking my reservoir to 25* though and I will be using a wave maker. If it slushes I’ll just add more into the mix.

$25/ gallon for food grade on Amazon, and they recommend changing like 1x / year.
 

Vale71

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At that price it must be recycled propylene glycol at best. I still wouldn't use anything that is not food safe in an application when food contamination is still a possibility. Besides that, if it's sold as ready-to-use without dilution then you have to multiply the price by 3 or 4 times to get the actual cost per gallon as compared to 100% propylene glycol which you will dilute at least 1:3 up to 1:4.
 
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Ridenour64

Ridenour64

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Yes the dilution May be a problem. I’ll be mixing it up in the next day or so and I’ll report any problems. Worst case scenario, it doesn’t work and I replace it with the real stuff. Will have only lost $7.50. On the other hand, if it works, I saved pretty good.

I’d be worried if the mix got into my beer even if it was 100% food grade. Especially after sitting in a cooler for months (years?).

At that, I would be circulating food grade PG through coils of a torn apart air conditioner and a cheap pond pump.
 
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Jag75

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From what I've read the glycol doesnt need to be changed . You have to add distilled water as it evaporates after time
 

501irishred

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If cold crashing the FV is in the plans, the glycol will need to be in the 26 to 28F area and that means even colder at the coil. No way water will do it.
Gotcha. The coldest I’ve considered taking mine was about 35, and water held up fine. Any colder than that and I could defiantly see where additional protection would be needed.

From what I've read the glycol doesnt need to be changed . You have to add distilled water as it evaporates after time
The glycol doesn’t go bad, but it can get contaminated over time especially in an open system. A visual inspection will show debris, and a quick test will show current freeze protection. Probably the only ones suggesting full replacement are glycol manufactures. :D

https://www.amazon.com/Refractomete...argid=aud-801381245258:pla-571022950495&psc=1
 
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Ridenour64

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The one that I saw recommending replacement was SS Brewtech and they mentioned longevity of the chiller. Not that I necessarily agree, but that was the source.

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Ridenour64

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I got slush at 26*. 3 gallons of RV coolant to 4 gal of distill. Might try another gallon of coolant or just keep it at like 27.
 

501irishred

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You might also try isolating that evaporator coil (barricading the side of the coil that’s open to the inside of ice chest). The idea is to ensure as much fluid is passing through the coil as possible instead of going around.
 
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Ridenour64

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I’m not sure what you mean by that, but the wave maker I have in there stirs things up quite a bit.

I’m also wondering if I got slush just because I went from room temp to 26 in a straight shot. I know the coil gets the coldest so even though the whole bath hasn’t got to 26, maybe the slush was just forming on the coil. I wonder if I’d get the same result once it warms up and cools down again. I have a 5* allowance set.

All of the slush was gone once the temp raised to 27 though.
 
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Bobby_M

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RV antifreeze is meant for winterizing the potable water system and is used at full strength. It would have worked for you without diluting it at all. When people mix glycol with water, that glycol does not already have water mixed in.
 
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Ridenour64

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Eventually I’ll dump an refill this reservoir and when I do I’ll use straight coolant. In the mean time I’ll just keep it around 27. I’m thinking I should be able to hangout at 35 or just above.

This is awesome though I can’t believe I waited this long to do this. No more ice! I’ll be crashing this Sunday though which is what I’m really excited for. I can finally use my unitank to its full capacity.
 

rkhanso

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FYI - I just built one of these this year and used it for the first time in August.
I am using just plain tap-water in the cooler/tank and was able to get it down to 34F with no freezing of the water....or none that I saw anyway. I use a very small wave/pump to circulate the water in the cooler/tank.

I also only needed to keep the cooler/tank 4-5 degrees cooler than my set temp in the fermenter. If I had a bigger gap than that, there was a larger fluctuation of fermenter temps. When I kept it closer like that, it kept a pretty consistent .25 degree each side of the set temp.

I did cold-crash the Belgian Tripel I just made -- well...cold crash may be a little generous. I dropped the temp to 37F in the fermenter for 3 days. The temp stayed rock-solid while the cooler/tank stayed at 33-34F.

I suggest using water a few times first if your air conditioner is used. Mine was VERY used and VERY dirty. I cleaned the coil the best I could with a brush and liquid, but after a few test runs, the water still gets pretty dirty (and stinky). I'm hoping that soon the coils/fins will be clean and won't dirty up the water any longer. Only after the water stopped getting dirty would I use Glycol.

I'm using a Raspberry Pi and CraftbeerPi software.

This is the fermenter temp:
Belgian Tripel final Fermenter temp chart.png


And a different time/date of my cooler/tank temps (not for the same brew as the graph above):
chillertankLongTerm.JPG
 
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Ridenour64

Ridenour64

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I didn’t pay any attention to cleaning the coils on the air conditioner. Since filling it I have not noticed any type of dirt in the reservoir. What I do have in the reservoir is plastic from drilling the holes in my cooler. I thought I got it all out but it’s apparent now that I didn’t. I got the big pieces out with my hands but I’ll need to get a fish tank net to get the rest out. Luckily it’s all floating at the top and not causing problems for my pump or wave maker. I’m not very familiar with raspberry pi or craftbeer pi but I can see you obviously have much better records than I do. I manually type all of my records into my notepad on my iPhone.

I plan on crashing for a week to hopefully have clear beer ready for the keg after.
Here’s my brew day
——————————
Blonde ale brew day
——————————
7.5 gallons of water heated
1 campden tablet crushed and added while heating
-chlorine smell was noticeable

Grain
-11 lbs of pale ale malt
-about 5lbs of this was Bries other 6
was viking pale malt
*i only mixed the malt to get rid of the bries
-.5 lbs caramel 20*L

7.5 gallon mash *not insulated
-Strike @ 156
-beginning temp - 150/151
.5 gal seems to be grain absorption

Around 7 gallon boil - just over
-.5 Oz centennial @ 60
-.5 citra @15
-whole whirfloc tab @ 15

6 gal at end of boil - 1 gallon boil off

While cooling, I accidentally left ball lock on uni closed, opened same with hose in the water (airlock) May have sucked water into tank. Unsure

Applied some co2 pressure and forced back out.

1.052 OG - projected was 1.048

Yeast pitched 8/25 around 8/9 pm. Bubbling slowly shortly after
Bubbles still slow morning / afternoon 8/26

Will raise the temp to 70* Thursday morning (8/29) and afternoon and hold for 7 days

Will dump yeast and then cold condition - 1/2 weeks

Dry hopped .5 citra 1115 pm 8/28
-I could not get the belt around the fermenter. It does not open fully
Set the temp to 70 hoping it will naturally raise.

Checked gravity 8/31
-1.010
Still cloudy, tastes good. Very fruity

9/4
-Dumped yeast - secondary
 
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Ridenour64

Ridenour64

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My unitank is really struggling to get to 37* it hit 37* last night in the initial crash, but since I’ve been up this morning, the pump is continuously running but it’s sitting at 37.5-38. The reservoir is getting down to 27* very comfortably so I’m not sure what the issue is. I even tried bumping the reservoir to low 30’s wondering if it was a freezing issue, but I wouldn’t think that to be the case?

All in all I’m not too concerned about it. I’m happy with 38*. But still wondering why the batch won’t go lower.
 

Dland

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Did you check return flow of coolant pump? I found mine was just sending a trickle of coolant though the system. First I thought it was obstructed, but it turned out cheap plastic pump had failed, the impeller broke or came loose. I got a new commercial grade pump and now system works a great.

All the glycol pumps I've seen from brew suppliers are cheap toys compared to what is available from commercial sources.
 
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Ridenour64

Ridenour64

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The pump is fine, I can see the water moving around in the reservoir. I’m using a 5xx GPH pump from harbor freight.
 

Vale71

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A delta of about 10°F sounds right for a SSB Unitank. The coil unfortunately offers a limited exchange surface, made worse by the fact that part of it is just cooling the headspace, so a decent temperature delta is required to achieve sufficient heat transfer. Add to that the sub-optimal insulation and it's likely that you've just reached the limit of your system, where even running continuously it can only remove the exact amount of heat that the tank absorbs from the environment thus reaching equilibrium.
When you actually have ice build-up on the coils the temperature will keep rising despite the pump running all the time. Once ice starts forming it will keep accreting creating a thicker and thicker insulation layer that will prevent any further cooling of the wort as all the cooling power will go into building even more ice. If this is not the behavior you are observing then there is no reason to think that you have ice forming in your tank.
 
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