Chiller heater... DIY style

Purchased a Cloudray 5200 chiller when my DIY mini fridge wouldn’t keep up with increased production. The wording on the web site said it had a heater… it was a typo.

Did a little playing, and came up with an aquarium heater that will fit down the filler tube. A little rewiring of the low voltage transformer supply wiring and a pair of temp controlled relays, and I have a working chiller heater.

Overnight temps around here have been in the low to mid 20’s (F). The ambient around the laser tube has dropped to the low 40’s, but the coolant has been staying in the mid 40’s to mid 50’s.

For details, check out the folder at the top of my Google Mod Page.

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Do you leave it running all night?

The temps last night got to 27 F, but it was pretty short time period and didn’t bother the laser.

I’ll go check your mods page. Now it’s off to bed…

Take care.


It is powered 24/7, but the temp relays turn the pump, and then the heater if needed, on at their set points.

The only other thing on constant is the web cam for me to keep an eye on it. The laser is in an insulated but unheated out building. It wouldn’t fit in the planned inside location by less than an inch. It came through the door, but wouldn’t go back in the spot we had planned for it.

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Figures, doesn’t it?

I’ve moved from the Phoenix valley area (where it doesn’t freeze) to the Verde Valley area. I was supersized it got as low as it did (27 F, out back). The wife advised I roll it into the house. Such a sweetheart…

So far we’ve had one cold morning. The machine is in the garage, that I think is insulated, but don’t know for sure… the door is insulated. There is also the home heater (gas) that lives out there so it produces heat on it’s own.

I’ll end up with an Arduino or something for a few days out there to get an idea of the temperature fluctuations and come up with something. The tube is working fine, I don’t want it cracked or damaged…

Take care.


Yeah, out there you could get away with a 110V baseboard heater thermostat and a heat lamp, worst case a little space heater.

Part of keeping everything together is keeping the area around the tube warm as well as the coolant. A guy on another forum had heat under his tube keeping it nicer and toasty, but the coolant in the bucket was just barely above freezing. Cracked his tube when he powered up the pump from thermal shock to the glass.

Yes, can’t send cold water into a warm tube…

My plan is much like you suggested, heat lamp/heater, to keep the area around the machine above freezing. Shouldn’t take much. I have to get me a remote temperature gauge for the garage.


Or point a cheap web cam at a temp gauge…I have an ancient one pointed at my control box so I can keep an eye on it from in the house.

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