u/OkaySureWhyNotIGuess

I have a "low mileage" GS3 which has a perplexing new symptom. When heating up everything is fine, flows well, no worries. Then past around 160-165F the group head no longer flows. The pump kicks on but nothing comes out. Steam wand and tea spout still run as usual. Pressure gauges read normally, but instead of water flowing out of the group head it drains into the tray, no flow alarms. And occasionally, but not always, pressing the "go" button just turns the machine off entirely.

Thoughts?