Hi,

I got this Bezzera BZ02S for free off of offerup, and I'm trying to figure out what is wrong with it.

As soon as I turn it on and fill it with water to the contacts, it starts pumping water out the brewhead, without pressurizing the boiler.

I think the issue is either with the brew switch or the controller itself.
Here's Why:
-As soon as the machine is turned on, it starts pumping till the water is below the contact line
-The brew switch is lit up, as if I had pushed it
-The boiler does heat up, but the is no pressure being created (the pressure gauge reads 0) and after a while, hot water does come out of the brewhead.

In addition; The cover of one of the wire terminals on the on/off button had black marks on it, probably from overheating. But I don't know if this points to controller issues or not.

I've heard that the Livia 90 is the same machine as the BZ02S, just with a better "shell", and this machine also has controller issues due to how close it is to the boiler.

I see that a new brew switch is ~$10. Should I try that route first before buying a new controller?

I'm assuming there is a solenoid valve for brew. If so, check that it has the expected voltage when "off". If so, check that it isn't frozen open with scale or failed seals.

If you are not familiar with working on live circuits, please leave the electrical testing for someone who is.

I'll have to test it tomorrow.

But I did look at it, and noticed that overfill tube(?) comes down from it. that tube was leaking quite a bit today when I was testing it.

I assume it's not supposed to leak that much, so if it is, could that be because the valve is frozen open?

I tested the voltage on the solenoid when the espresso machine was off, on without pumping water, and on while pumping water.

When it is off or on without pumping water, the solenoid is at 0 VAC

When it is on and pumping water, the solenoid is at ~114VAC.

Is it worth taking the solenoid apart and seeing if it is frozen open? Or should I just run a descaling solution through it?

If you remove (and safely insulate) the wires from the brew switch, does it stop acting like the brew switch is on?
Can you test the brew switch separately from the machine with a multimeter?

That was it! Come to find out, the push button had a rusty spring that wouldn't allow it to return to the off position.

I actually just rigged it up to pull a shot, to look for other issues (I just stopped the shot with the on off button), and saw that the shower screen had a leak, so I'm cleaning that now.

The steam line also has a leak, so I'll solder that closed.

The answer to this whole situation was very obvious, thank you for pointing it out, JRising!

Onto the rest of the repair