I've experienced something similar when I do back to back caps. Few things I've found:
1) if my machine filled the steam boiler in the morning, I don't have this issue on the first or second cap in the morning
2) if my machine did NOT fill in the morning, I rarely experience this on the first cap in the morning, and sometimes experience on the second cap (the exception is if the steam boiler refills after my first cap, then my second cap is perfect)
3) if I leave the machine on all day, the steam boiler sometimes loses water by way of the spitting and light hissing, and then it's anyone's guess if my first cap has a problem
Here's what I can recommend - if you know the boiler is full, steam away. If you suspect that the boiler might not be full, run some hot water out of the water tap, forcing the boiler to refill, wait 10 seconds for the boiler to heat back up, then steam away. I have no idea if this is a flaw of ECM, a flaw of a leaky steam boiler due to minerals in the o-ring, or a design feature of E61s in general. I keep my machine at 263 and stopped having this problem months ago, but it's because of the recommendations above that I myself follow.
Equipment doesn't work? Troubleshooting? If you're handy, members can help.
- Supporter ❤