I recently purchased a Fiorenzato Colombina. It has a gauge for brew pressure, and while the instructions recommend adjusting your grind and tamp to achieve the appropriate pressure, I have found this impossible without getting much too great a flow rate. I have read that this machine lacks an adjustable OPV, and if one believes the gauge, the existing OPV is set very high (at least 18), I did take the case off the machine, and there are two pieces of hardware coming off the pump that feed back to the water supply. The pump output is shown in the following two pictures:




Can anyone identify these two pieces? Is the second an OPV? Is it adjustable?

Thanks,

Mike

Hi Mike

I don't know the Fiorenzato Colombina machine but it does look like a standard Heat exchanger E61 group with a vibe pump. These pumps are usually accurate and it should produce ±9bars of pressure.
Have you tried grinding your beans even finer? if so, does your pressure gauge ever read more than 9bar?

If I were you, I would insert a blind filter(one that has no holes: http://www.1st-line.net/cgi-bin/category.cgi?item=R037), start the shot and see what the pressure gauge reads. If it stays on ±9bar then you know there is nothing wrong with your brew pressure, and that the problem lies with your grind that is to coarse, your beans are too old or you have to work on your tamping technique.

Kind Regards
Renier

Mike -

If you bought the machine NEW and it is still under warranty, I would discuss these pressures with the dealer. Yes, 18 bar is WAY TOO HIGH and is almost indicative of an inoperative OPV.

But, to answer your questions, the OPV is the brass fitting next to the side rail of the base. The smaller hose is attached to what is called the pump priming valve. That OPV MAY be adjustable but first one has to unscrew the hex/barbed fitting and see what is inside. Depending upon where on the boiler the SS flex line attaches, you will have lots of water leak out so tilt the machine in the direction of a sink if you choose to do so.

See this section from the Resources part of this site: http://www.home-barista.com/espresso-ma ... -t420.html

Can't help with OPV adjustment on Colombina, suggest calling 1st-Line. However if you wanted to bring your machine over to my cafe downtown Vancouver sometime could help you confirm it's operating properly. Have a PF pressure gauge to verify pump pressure, Scace Thermofilter to dial in HX surf method and plenty beans always on hand to test shots.

Perhaps the OPV pictured in the lower right of your photo has a shim adjustment like this one from the Giotto Premium?


From How can I adjust the brew pressure of a vibe pump espresso machine?

Thanks all for the replies. The Colombina is a single boiler, non-hx. I took what was pointed out as the opv apart, and this is what I found:




It looks like a non-adjustable opv. The good news is that when I put it back together, and used the blind pf, the pressure maxed out at 10.5 bar. So, it looks like the original issue is that it was stuck.

It looks like my options at this point are either to buy and install an adjustable opv (Chris's coffee has one with good reviews), try cutting the spring, or live with 10.5 bar.

One last question, if I do replace the opv, is there any trick to removing the current one, or should it just come off with ccw rotation?

Do not cut the spring - that is a "one-way street".

Why not install an additional teflon washer (buy several) and possibly reduce its thickness with sandpaper on a piece of glass? Me thinks that 1-1/2 sealing washers (total) would put you in the "correct" ballpark.