I have a Breville Barista Express (BES870XL) which just turned a year old this month. I've tried to keep up on the maintenance throughout the year by using the backflush tablets and descaling powder when the machine indicates maintenance is needed. I completed a descale this week using the descale powder and when I put the machine into descale mode and completed first flush through the group head, all was working as expected. When I turned the steam lever to steam, no steam would come out of the steam wand. Instead, water came out of the group head again all over the drip tray. When I turned the steam lever back to neutral and then to the hot water setting, the same thing happened.

I shut the machine off and let it rest and came back to it about 30 minutes later and tried the descale process again. This time, when I turned the steam lever to steam, no water came from the group head and the machine flushed the steam wand as normal. I completed the process and then flushed the reservoir with fresh cold water which I then flushed through the group head, steam wand, and hot water spout.

After I took the machine out of descale mode, I tried pulling a shot of espresso. The shot pulled normally. When I went to texture my milk, the steam pressure from the steam wand seemed like it was cut in half from where it normally was. Additionally, the wand shot quite a bit of water out before converting to steam which didn't used to happen to that extent either (usually it was a quick purge but now it's 5-10 seconds).

It sounds like there may be some hard water buildup that broke free during the initial purge of the group head that's now blocking a valve somewhere and restricting the steam pressure. I don't know enough about the internals of the machine to take it apart to try troubleshooting further.

Any tips on next steps here?