Coolant detection?

So, this is probably / hopefully a dumb question, but how can I tell there is actually coolant in the loop?

When I first got my GF I seem to remember some tiny bubbles in the tube – I’ve used it a few times, but this morning it didn’t want to calibrate - so I opened the door, had a look around, etc. While doing so I realized I couldn’t see any coolant in the tube, but I cannot tell if it is completely full, or completely empty :slight_smile:

I tapped the side of the coolant reservoir, and it sounds empty, but I’m not sure (and not, I cannot see coolant anywhere!) – AFAIK, there are coolant temperature sensors in the loop, but if all of it has managed to leak out (and evaporate / soak into my carpet) would the sensors detect this? Does it monitor the sensors and build a profile (which would not be correct if the pump, etc was just sucking air).
Is there any way to tell if there is actually liquid the system, or should I jsut assume that it would have failed if it somehow leaked during shipping and I didn’t notice it…

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Actually not a dumb question at all…i had the same questions with the PRU.

It’s in there, you just don’t see it since all the air gets pumped out (the little bubbles you saw) the first time you fire it up.

It took a lot longer to pump the air bubbles out of the Pro model when I got it, but i suspect they transported the thing upside down the whole way.

Anyway, I can’t see anything in there now either.


It is full so you can’t see it. There are sensors that shut the machine down if it gets too hot, so if it were empty it wouldn’t work at all.
If it had leaked there would be evidence of it.


Awesome, thanks!

That is kinda what I’d assumed, but I wasn’t sure if the sensors were only in the liquid loop, in which case they might not be reading if empty, as the little pump might not do a good job circulating the air / the thermal conductivity of air is very different to that of water / liquid.

Anyway, thanks for putting my concerns to rest!

In addition to the coolant temp sensors, there are also coolant flow sensors. The system can tell if the coolant flow is sufficient, or, in the case of no/low coolant, if it isn’t moving at all.


Excellent (and reassuring!).
Thanks for letting me know – I did try peer around the corner with a flashlight before posting (looking for leaks and evidence of sensors), but wasn’t able to see anything.

Nice to know that an undetected leak would, er… be detected :slight_smile:

The easy way is if it’s lasering. The tube will self-destruct in about 30 seconds if there’s no cooling fluid :slight_smile: CO2 lasers don’t like running without cooling :smile:


@warren The coolant is typically invisible, and there are sensors to monitor coolant.

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