So, a few hours later:

Everyone was right!!

a. I cleaned the machine thoroughly. Apparently the person who sold it to me and said that he had done so... did not. That would help to also know if overpressure was related to gathered material in the pipes.

b. I checked the T-Fitting. It is an OPV! I was able to set the pressure at 9 bar. Only problem is that the threaded insert is now sitting almost at the end. No water is being spilled though. The fitting is also very sensitive now to the smallest turn of the silicon pipe.

c. NOw the maximum pressure is 9 Bar, but another problem comes up. Since it is warm water that is routed back to the container, through the OPV, the machine loses temperature too fast. There is not enough warm water for a double coffee, depending on the timing.

Therefore, a cold water OPV is necessary.

Thank you all guys! Will let you know how it went.

It has been much simpler than that, to adjust the valve.

I created a coffee puck as compressed as reasonably possible. That brought the running pressure of the machine to 14-15 bar. Then, with the coffee machine working and extracting coffee though that tough puck, I have adjusted the valve, so that the pressure was reduced to 9 bar. Since then, I have been getting precise, 9 bar extractions.

Now using the same technique, when the cold water OPV arrives, I will adjust the warm water OPV at 11 bar and the cold water at 9. It does make some sense, I reckon.

here is how the OPV looks when opened completely and how it looks when fitted. I am kinda worried of the rubber just hanging there. The thread is now so loose, that turning the hose a bit, can also turn the threaded insert.

I hugely appreciate the time everyone has taken. I do understand now better, how this can turn into a small addiction and I enjoy the process a lot. Sure, I don't have the 3000k to buy the perfect machine, but I do take enjoyment from making this thing work, more than the 3k.

So, what do you think of my option for an OPV?

https://www.bluestarcoffee.eu/en/Vibiem ... -5613.aspx


Any other upgrade you would be proposing, now that I am placing the order?

Kind regards, Tony

As a stop gap, there has been some recent conversation around how much pressure is lost across the brew valve, and it seems that at least 2 bar pressure drop is reasonably expected. You could minimize the OPV back to your tank by setting the brew pressure to 11 bar and expect to get 9 bar at the puck.

I realise now better the meaning of this. To be honest, I have experimented a lot with adjusting the pressure, but simply opening the steam wand, while extracting the coffee (don't ask...). In all cases, I have noted a sweet balance, when the pressure gauge shows appx 9. More and it becomes bitter, less and it becomes cowboy style boiled water+coffee.

Therefore, I choose to trust the gauge and use the number 9bar as a standard, not because I have read about it, but rather because I have made sure it works.


once again: A HUGE THANK YOU TO ALL OF YOU!

PoorAfficionado wrote:I hugely appreciate the time everyone has taken. I do understand now better, how this can turn into a small addiction and I enjoy the process a lot. Sure, I don't have the 3000k to buy the perfect machine, but I do take enjoyment from making this thing work, more than the 3k.

So, what do you think of my option for an OPV?

https://www.bluestarcoffee.eu/en/Vibiem ... -5613.aspx


Any other upgrade you would be proposing, now that I am placing the order?

Kind regards, Tony

That one is a great option. Positioned correctly, you could make it adjustable from outside the machine! Would require drilling a small hole, but that's a small sacrifice for such functionality.

Hi all,

thank you for taking the time to answer my questions. A small update.

I have intalled an OPV on the cold side. OPV was delivered without Teflon Tape or this other rope-thing used to seal threads.

Currently, the coffee comes out, without the warming element activating. This is as expected.

The coffee tastes life-less, almost burnt.

Indication on the Manometer is exactly 9bar.

Machine is noisier, as the pump was kinda moved, because of the new installation.

I am excited with my new modding hobby Coffee again.. not so good