Submersible pump in glycol - stuck impeller?

[bcrawfo2]

I have this pump in my glycol reservoir https://www.amazon.com/gp/product/B002JPIQ1Y/?tag=skimlinks_replacement-20
It’s been working great. Last night before bed I started a cold crash from 70 and took it down to 35. This morning I woke up and saw it had gotten to 35 and was working its way back up. I watched 37, 38, 39, 40, 41, 42. I checked my BCS thru all of this and saw it was calling for the pump to be on. I went down and checked and saw the relay was on and heard the pump working. I saw nothing coming out of the return from my cooling coil. I was able to blow thru the return, thru the coil, and back thru the pump.
Finally I took the filter cover off and could see that the impeller was moving, but not spinning. Kind of like it was juimping and then getting pushed back. I removed the impeller cover, took the pieces apart, and reassembled and it’s all good.
Any ideas? The pump is just a few weeks old and was taken straight from the box and placed in my glycol.

 

[Tartan1]

What is your glycol/water ratio? Viscosity will increase if too much glycol is used as a ratio to water as it chills down close to freezing, it may be too much (thick) for this pump to handle.
Also the description of the pump from the link you provided indicates "This Active Aqua submersible pump designed specifically for hydroponic systems" so it may not work in colder environments such as a chiller, and I would assume it means water/nutrients only.
Anyway just a thought.

 

[bcrawfo2]

My glycol mix is about 33% to 67% water and i keep it at about 25f.
Its weird, you can see it got there and maintained for a while. It seems like one time when it kicked on something went wrong

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