new machine pump output question? wonder what the weird t-fitting is on the vibe pump or if its supposed to be some kind of opv, not used to machines this small i see no way of adjustment at all. i want to get my pressure portafilter set up this weekend to see what im running for pressure, upon opening i dont see much for adjustment.

Disconnect the return hose and you should be able to rotate the fitting by hand or maybe a tool will be required, it looks similar to the current bezzera opv where the fitting for the return hose screws in/out compressing a spring to set the release pressure.

stuartmac wrote:wonder what the weird t-fitting is on the vibe pump or if its supposed to be some kind of opv, not used to machines this small i see no way of adjustment at all. i want to get my pressure portafilter set up this weekend to see what im running for pressure, upon opening i dont see much for adjustment.

Your notes all seem to be right.

Its position indicates it is in fact an over pressure valve (OPV), keeping the pump outlet pressure at a fixed level by allowing excessive pressure/water to flow back to the pump inlet. Usually, OPVs are adjustable by loosening a locking nut and turning the OPV outlet clockwise (make sure not to twist the tubing) to raise pressure and counter-clockwise to lower it.

I'm not familiar with this particular model. Some OPV are adjustable, some are not. It seems that your OPV outlet has only one nut (no locking nut?); it may not be adjustable. On older Rancilio Silvia models, the OPV was not adjustable but you could still add spacers (washers) in between the OPV body and nut to lower the pressure (raising the pressure would have then required a stiffer spring). Google should be your friend if you want to look at this possibility.

Of course, I assume you did test the group pressure and confirmed that it is way out of where it should be (8.5-10 bars should be ok) before thinking of OPV adjustment.

This is from the Bezzera Giulia, OPV adjuster does not have a locking nut

Looks like an OPV to me. You should be able to turn the nut with a box or spanner wrench. You will want to disconnect the return line when you adjust it or you will twist the silicone hose. I have seen twisted hoses twist the setting back to where it started over time.