Here is a photo of the pressure gauge on the machine. Temperature and pressure are fine.

As a side note, I see zero reason to "upgrade" to a dual boiler and if I replace this thing it will just be for a vanity purchase of something I think looks cool or practical purchase like a GS3 to fit it in my house easier. I'm perfectly happy with my hx.

So yeah, it's a heat exchanger machine and the pressure will be stable at this level for long stretches of at least a week at a time, but there is something making it overpressure and blowing the steam release valve "sometimes".

Any ideas on what to tackle? I guess it could be the pstat but if it's stable for at least a week at a time and the pstat is new, is that still the first place to look to replace parts?

What is the reading on the boiler pressure gauge when the safety valve is venting steam?

The steam gauge is the only gauge that changes when steam is released. Steam vents as at 1.5ish bar pressure.

Assuming we are talking about the pressure relief valve and not the safety valve? These are usually two separate parts. We are also assumming that the gauge is always reading the correct pressure and not occasionally sticking.

If the gauge is reading 1.5 bar only when the safety valve opens and a more appropriate pressure all the rest of the time then I'm going to assume they are both working correctly (or at least as correctly as those cheap gauges ever work.) That leaves a sticky relay in the p-stat as your most likely problem.

The gauges are new, too, actually. I've replaced quite a lot on this machine, could have purchased a new one with the money I spent on incremental repairs lol. I think the gauges are fine because, with respect to the steam gauge, it goes up when the pressure goes up and appears to show pressure properly. The brew gauge is a non issue.

The question is, why is the machine fine most of the time, and then sometimes producing too much steam?

Here's the diagrams:

In an attempt to establish a common terminology:

Pressure relief valve,also referred to as safety valve: vents the boiler in case of a faulty situation.
Vacuum breaker,also referred to as Anti-Vacuum valve: seals the boiler when up to pressure.

For visual reference,
https://www.espressoparts.com/3-8-nuova ... fety-valve
https://www.espressoparts.com/1-4-steel ... -valve-new

damonbowe wrote:The gauges are new, too, actually. I've replaced quite a lot on this machine, could have purchased a new one with the money I spent on incremental repairs lol. I think the gauges are fine because, with respect to the steam gauge, it goes up when the pressure goes up and appears to show pressure properly. The brew gauge is a non issue.

The question is, why is the machine fine most of the time, and then sometimes producing too much steam?

Here's the diagrams:

Exactly!
Item #11 on the diagram is the Vacuum breaker.
Item #14 on the diagram is the Safety valve.

So we are on the same page now
Which one of the two is steam comming out of?

If it is from the safety valve like you mention in post#1,then it is likely that there is a problem with the boiler autofill function causing the boiler
to overfill.A faulty autofill solenoid valve or a wire on the autofill probe coming loose, causing the boiler to overfill.

Also have a look at :/espresso-m ... 26494.html

damonbowe wrote:
The question is, why is the machine fine most of the time, and then sometimes producing too much steam?

Check the wires of the probe sensor #15.

I just wanted to say thanks, I'm trying to get to the point where I can dive into the machine but this whole virus thing is throwing me off. My kids will run off with all the parts before I can get the machine put back together and I don't have a good space to work at home.