I've started using the Mega II for the first time in several months. I notice that when I pull a shot the Pump Pressure gauge goes to 190 PSI. The shot is ok, but that seems like too much pressure. Anyone know what the PSI should be and moreover, how do you adjust it. bz

9 bar is ~130 PSI. 190 psi is 13 bar, so yes, that does seem high. You may want to adjust your over-pressure valve. It may look like one of these.

Cheers,
Colin

Thanks to you both. I am going to take the covers off and look for the OPV. bz

There's no OPV to locate per se, it's part of the pump itself. Astra uses Procon rotary pumps (assuming yours is the original pump?). The pump is on the right side of the machine (brass part connected to the electric motor). Next to the inlet end of the pump there will be a screw OR a brass cap covering a screw. So unscrew the brass cap (that's how my procon is), but either way, turn the screw clockwise for more pressure, counter clockwise for less pressure.

Joel, thank you. I took the covers off and I see what you are talking about. My machine does have the procon pump. However, I see another valve directly in the middle and upper back of the unit. It looks like an OPV (expansion valve); what is that? It can be adjusted but I didn't want to touch it without knowing more.

Moreover, since you also have a Mega II, what does the gauge read on yours. My pump pressure varies from 130, idle, to 190 PSI when drawing a shot. The boiler pressure stays at 1.5 bars all the time, idle or drawing.

I've yet to pull a shot. Currently descaling everything and getting the groups cleaned up; should have it up and running this weekend. So I don't have any info on the gauge readings yet.

Not entirely sure what you're talking about the OPV halfway up the back in the middle. I have a complete parts list and I can reference when I get home this evening. There is a small contraption with a copper tube running to the drip tray, but I didn't notice it was adjustable. Is this what you're talking about? It's obviously for excess pressure/water of some sort, but that wouldn't be used as an OPV to adjust the brew pressure.

buzzon wrote:I see another valve directly in the middle and upper back of the unit. It looks like an OPV (expansion valve); what is that? It can be adjusted but I didn't want to touch it without knowing more.

... My pump pressure varies from 130, idle, to 190 PSI when drawing a shot. The boiler pressure stays at 1.5 bars all the time, idle or drawing.

Take a picture of the other valve and someone should be able to clarify what the discrete valve is. Usually a rotary pump machine relies upon the integral bypass adjustment to set pressure. And vibratory pump machines have a separate OPV instead. But some machines will have a rotary pump/bypass adjustment and an OPV. If it is an OPV, then you would adjust your bypass screw to get 130 psi during a shot & set the OPV somewhat higher, as a secondary relief. Or the valve you are describing may be something different. I wouldn't adjust it until you confirm what the valve is.

As to your pump pressure, at idle the pump will produce no pressure. So depending on how your machine is configured the gauge would then read zero or the water line pressure. So 130 psi when the pump is idle, sounds like your water line pressure is 130 psi. That is a high pressure to start with, most people have a line pressure about half that. So you really need a water pressure regulator to drop that down to something like 30 - 60 psi. Then adjust your bypass screw for 130 psi during a shot.
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Thanks. I adjusted the procon down to 130 PSI and all seems better. bz