My LMLM has a vaccum breaker valve that is acting up (and will be replaced tomorrow during service), and loses steam a lot. I recently noticed that the following would happen during brewing. If I start brewing, sometimes after a few seconds brewing stops, and then I hear a steam noise (which I think is heating; there is no pump activity). Sometimes the machine will then blink the red LED to show its unhappiness with the situation.

So I am wondering if the brewing shutoff happens as a result of the need to get steam (even though I am not using the steam boiler at the same time) or any heating (as I may be wrong and it may be the brew boiler that is heating, though that seems less likely). That would make me hopeful that changing the valve will resolve the issue, versus looking at a new logic board. (I guess one eventually updates to the connected board that way .)

I would call Chris at La Marzocco for assistance. The issue may not be the vacuum breaker.

Are you using reverse osmosis water by any chance?