Hello everyone, I am having some issues with my chiller. I recently topped off its reservoir and It was working fine prior.
Now only the outlet side of the chiller and solvent tank are getting frosted. Chiller cycles down to -40 fine and cycles but i can see from the inlet side of the solvent tank it is a trickle. I tried priming the line and bleeding air from each connection while circulation was on. Possibly didnt do it long enough/properly though. Have had to bleed chillers for air before but never had this much issue. This is also my first “closed loop chiller” and its been nothing but head aches between the bypass and bleeding issues.
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What is your thermal fluid? I believe an ethylene glycol mix will slush at -40C.
If it is a glycol based fluid I would also double check to see if the bottle you have/filled from is a concentrate or pre-diluted bottle. If so maybe you topped off the unit with concentrate and once it gets cold becomes too thick for the pump to move.
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Is it possible you have a new restriction in your system? As zaxtol says check your coolant mix but if it’s barely trickling with pump running I’d probably see if you run a loop from outlet to inlet if flow improves, the pumps on these dslb type chillers usually aren’t that powerful and struggle to overcome much head or restriction
Its a propylene glycol/water mix at 60/40.
Same bucket i used originally to fill it when it was working fine and when i originally bled it right after the chiller was running, it was not really viscous at all. Im thinking some kind of restriction i cant find or vapor/air locking or hoping anyways
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When i fully open the bypass it seems to run from outlet to inlet really well and ices up everything. We did have a small pinch on the inlet side after refilling but fixed that.
I forgot to upload this video. This is inlet side of the solvent tank juet trickling. The confusing thing is the outlet side from chiller into solvent tank seems to be flowing hard. So maybe a vapor lock in the coil of my tank?
You could try putting a gauge and a tee in your outlet and see what kind of pressure you have, that would tell us if you are trying to push thru a restriction of some sort
You don’t say what all its hooked to, but as I said these things don’t really have all that strong of a pump. Having watched your video, I agree that flow is not as fast as it should be, but you shouldn’t have a situation where you’re pushing into the top of a jacket and collecting out the bottom either, you should really have your ports aligned in such a way that they fill from the bottom and push air out the top to make for easy bleeding/burping and minimal spots for air to get trapped in.
In order to give you good advice you need to give us a full picture of what exactly it is you are doing, including distance and diameters of your hoses and what vessels they are hooked to and where they flow in and out
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USA Labs support usually is very helpful, did you try reaching out to them? Tech@usalab.com
Otherwise, the cause may be an issue with the aulank circulator pump. We had a similar chiller and are experiencing similar problem.
Yea we tried a lot of things while emailing back and forth with them. Still no fixes but last recommendation was to swap the transfer fluid for ethanol since the glycol mixes sometimes are too viscous for the pump to move. Hoping its that easy of a fix, waiting on ethanol order now.
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Im thinking maybe its the pump if not just the fluid being too viscous. The compressor seems to read and work great? Knock on wood.
Have you confirmed that your hoses are oriented correctly?
As mentioned by greenbuggy, the video that you posted previously and said is your INLET appears to be on top of your external vessel which would be incorrect (if so). (Didn’t see if this was addressed)
Another thing I thought I might ask is, did you burp/bleed the system when it was cold? I believe this process is more effective done warm, I did my air purge at 20C on my hubie doobie. I believe this is also recommended per draining/flushing your system as well.
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I can post pictures shortly, but i am pretty sure the hoses are proper. By inlet , i mean that is the hose from which the transfer fluid flows out of my solvent tank coil and back into my chiller. Plus its worked in the current configuration for over a year, which hopefully means it was set up right? But stranger things have happened.
I actually did not try burping it while it was cool, warm only. I will keep that tip in mind thank you!
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The pump manufacturer recommends that the fluid viscosity be lower than 50 cSt, even at low temp
The viscosity of the propylene glycol/water mix at 60/40 at -40 C is too high for the circulation pump.
@Wade I think the real question is whether op changed the concentration of glycol when they topped up their system. A refractometer isn’t very expensive to confirm actual mix ratio
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Gotcha, yeah hopefully that is an easy fix.