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My Vivaldi II har worked (almost) like a charm for many years until now.
The indication for the steam boiler seems to be working fine, but the indication for the brew-boiler is seriously wrong.

When the machine is turned off the gauge reads almost 15 bar!
When the boiler is at working temp the gauge reads about 7 bar.

Pulling a shot:
As the preinfusion starts the gauge vibrates a bit (like normal) and falls to about 6 bar.
When the pump activates the gauge stays at 6 bar!

This is confusing to me….

My initial reaction was that there was something wrong with the pump.
But my thoughts now is that the there is something wrong with the pressure gauge.
I believe that when the machine is turned off, the gauge shows the pressure from my water inlet.
Before I had these problems the water pressure from my inlet was not 14bar!….. I think it was about 5-7 bar.

Anyone has any idea what might be wrong?

I'm grateful for any help I can get.

If your coffee is still good the pump must be working correctly. Everything that you describe sounds like a failure of the gauge.

If you turn off the water supply and disconnect the water hose from the VII the pressure gauge should show zero. If it does not it probably is the gauge.

Good idea chas!

When i disconnected water supply, the gauge went to zero (damn... this could get expensive)
I think there was some kind of relief of pressure when i disconnected.

Weird thing is that when connecting water again the pressure reads about 6 bar.

Same thing as before... when i activate the pump the pressure stays at 6 bar but the gauge is vibrating a bit.

Any ideas what could be wrong?

Here is a follow-up of the problem in case anyone else experience the same issues.

I ordered a new pump (from elektors.it) and installed it.
Behold!!! My pump and pressure gauge seems to work fine.

But... Now i have a new problem

When i start the machine it seems to work just fine, but as the temperature rises so does the pressure!
And it keeps on rising until i draw a shot. The first splash (preinfusion) is quite violent indicating that the pressure is indeed high in the boiler. After that the pressure seems to be normal as i continue to draw the shot.
After the shot the pressure returns to normal for a short while until it starts to rise again.
When i turn the machine off the pressure-build stops.

Now.. what wrong this time?
Please help

//M

Have you adjusted the expansion valve as explained here: Adjust Expansion Valve?

Nope, i have not. Problem is I don't own a portafilter pressure gauge.
I guess I could do it using the gauge on the machine(?) but I don't trust the gauge. It could perhaps be that the gauge is broken!

Since I replaced the pump I´m still having problems with the pressure in the group but now the problem is different... before I had no pressure.. no I have to much pressure... weird.

This time the pressure started to build the second I turned the machine on... I let it go up to 14bar until I pressed the button to draw a shot (with a blind portaler in). The pressure went to about 8-9 bar (my setting when pulling a shot). When I pressed the button again to stop the shot the pressure immediately went back to normal and then started to build pressure again.

The machine was on its "back" for a couple of weeks as I was waiting for the spare parts... could it somehow have produced the new problem?

My next step is to pick the expansion valve apart to look if there's something stuck in it.
Next maybe I should buy a new pressure gauge(?)

Any other suggestions ?

Based on your earlier information, I am thinking it is likely that your pressure gauge is OK.

The coffee boiler pressure only really matters while you are pulling a shot and it sounds like you are seeing a steady 9bar at that time.

In between shots it is OK for the pressure to drift so long as it doesn't exceed 12bar. SInce yours is exceeding 12 bar the fix is to clean and adjust the expansion valve. You can do that with a blind basket using the built-in pressure gauge.

In the long run I would recommend buying or making your own portafilter pressure gauge. That is always useful as a final check that the internal one is OK. An external PF pressure gauge should read the same as the internal gauge when using a blind basket.

First... Thank you for your help Chas!

The expansion valve is now clean and adjusted to 12.5 bar according to the pressure gauge on the machine.
For a short while I was a happy barista and it looked like it was I working order again... but...

Next time I turned the machine on the pressure in the group boiler immediately stated to rise... and after a couple of seconds it was at 12.5bar and the expansion valve opened according to my setting.
So there is still something wrong with the machine.... before my problems started (initially with the pump) the pressure was always steady at about 6-7bar (with the machine on as well as off) but now it is steady at 12.5 bar with the machine on (thanks to the expansion valve).
For some reason the pressure in the group boiler is way too high until I activate the pump.. then the pressure falls to my setting at about 8-9 bar. As soon as the pump turns off the pressure starts to build again.
Are there some kind of pressure relief thing-a-mojigg (other than the expansion valve) that is stuck?
Weird thing is that the pressure build start immediately as I turn the machine on... loooong before the temperature rises to about 90 degrees (C)

Arrrggghhh.. I want my espresso!!