Was using my machine today and and later on, after two hours water started to pour out from the over flow /over pressure tube at the bottom.
It is plumbed in
Turned the machine off and the water off, let it all cool down.
When I turn on the water again it just lets water out of the tube - had a look at the overpressure valve (the one that is enclosed) and this is letting the water out to the tube at the front bottom.
Also pulled apart the vacuum breaker to check the o ring - this was all replaced in a major service 6 months ago.
If I turn the machine on it makes no difference and water will pour from the steam wand if I open it and this stops the water flowing out the bottom.
I would very much appreciate some assistance with this.
Thank you for any suggestions or please let me know if I should provide some more info.

Hello Ricardo and welcome to HB!

Your boiler fill valve is most likely being held open by a bit of grit or has a failed seal in it, leading to line pressure flooding the steam boiler.

You'll need to shut off the water supply to the machine and drain the excess water out of the boiler. Changing the solenoid valve will fix your problem, but it could also resolve itself with a couple cycles once the boiler level is low enough to call for water again.

What type of filtration do you have ahead of the machine?

Cheers and good luck!

- Jake

Jake a hero!!

After a cycle or two the valve started working correctly !

I would also check the incoming line pressure; it may be too high. La Marzocco recommends 45 PSI (approx. 3 bar).

And verify that have proper filtration going to the machine. If you don't at least have a sediment filter, future leaks are almost certain.

Thank you Jake - I have triple filtering and we checked the water pressure on installation and again early this year.... but I have had the machine since 2016 so I guess age of the valve is a factor ... maybe time to replace it.

Just keep an eye on it.

If it happens again, looking further into the root cause will pay dividends!