Yellow light, says cooling and liquid inside

Yellow light came on yesterday and the machine said home. Was able to get it working again. Turned it on today and started cutting. Within a few seconds yellow light came back on, says cooling and in this little reservoir in front of the exhaust fan there is clear liquid pooling. Could it be the laser tube coolant?

Not sure what is going on. Wondering if the tube cracked somehow.

Could be the tube, more likely a tube or fitting.


Take a close look around the pump that connects to the tank. Where the hose leaves the pump would be my suspect, because the pump slightly pressurizes the flow there. Mine doesn’t have it, but I have seen a picture of a newer machine that had a band clamp on the coolant hose. There would be a reason for that modification.
See any tiny bubbles in the tube? That would indicate a low level in the tank.


I’ll have to look and see if I can figure it out. We just got this one as a replacement because I had a problem with the last one. This is the 3rd machine in 2 years. I did notice bubbles on the beginning when I first used the machine but I thought that was just from it having been shipped and moved around so much.

Now the laser won’t even fire up so I can’t even check for bubbles

That’s completely normal and expected.


That’s right. They all have air in the tube at first, and it purges in the first minute of powering on. If the tank is low there will be a stream of tiny bubbles that don’t go away.

Nothing? Not even the yellow light?

The yellow light comes on and it says alert cooling

If your machine is in an air conditioned room and is kept connected to a vent that goes outside, it could be condensation from humid outside air hitting the cold inside of your machine. How cold is it where your Glowforge is? It needs a 75F or cooler room to run, or it will keep “cooling down”.

Right down behind the pump, there is an electrical connection I believe senses temperature. Make sure that is plugged in.

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The vent is not connected to the outside when the machine isn’t running. It isn’t condensation all over. There is just fluid in the one spot in the picture.

I’ll check that too. Thanks.

Not sure what exactly to look for but here’s a picture of that area

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It’s in that last picture, that small connection next to the pump. It looks fine. No further communication from support?

They just responded. They’re sending a new unit again. This will be the 4th one in 2 years. Good thing I bought the extended warranty.


Hopefully, that will do it for you. Mine is on its 6th year, may you have as good an experience. :sunglasses:

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Thanks! I really hope the 4th time is a charm!

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