Lets see if this is going to be something simple.
First put the back flush disc into the portafilter, put it into the brew group and raise the lever all the way up. It will take a few seconds for the filter basket to fill with water and then the pressure should rise. When you do this does the pressure go to 10 bar?

If it does not go to 10 bar then the OPV should be adjusted to get it to 10 bar.

If it does get to 10 bar then grind your coffee finer to slow down the flow. Because if your flow is to quick the coffee is to coarse and you will not be able to build up any pressure on the coffee. Plan on getting 2 ounces in around 25 seconds.

If this is not it please e mail me your phone number and we can figure it out quickly on the phone.
todd@wholelattelove.com

Thanks

Todd
Whole Latte Love

Hi Luis. Just saw your video. My take is simply that you have a defective machine. Return it.

Previously Eric wrote:

The dripping from the "spigot" which comes out of the faceplate during your short initial flush of the machine is normal. That is flow from the vibe pump's priming valve/air release valve.

That same dripping from the "spigot" during brewing is also normal because the OPV (over pressure valve) relief flow and the pump's priming valve flow are tee'ed together inside the machine and the discharge of both goes to the spigot.

Hi Eric, I've a Brewtus IV Vibration pump too and also experience water coming from the "spigot" while brewing at 8.5 bar. The brewpressure is limited at 10 bar. I would think that the OPV would only spit out water if the pressure would come above the 10 bar, not while brewing at 8.5 bar. But my knowledge of the working of an OPV is very limited. Do I understand correctly from your quote above that it is normal? Could you explain why? Thanks a lot!

Kind regards,

Marc

Could you explain why?

Sure - I'll try. Please realize that we have an either/or situation here.

First, you need to take into consideration that there is a length of silicone tubing between the point where the flow starts and the exit at the drip tray "nozzle". So, even though the valve(s) may be closed during brewing, the water in the hose(s) will still drip . . . drip . . . drip.

Second, during brewing, the priming valve should be shut. It is designed to close at 6-8 bar per the specs on the Ulka drawing I have. If your OPV is/was adjusted such that a 10.0 bar pressure produced a relief discharge from it (and it alone) of a steady drip, that is OK. If you put a blind basket in place and "brew", the steady-state flow into the drip tray would be 260 ml/min at 9.0 bar and 225 ml/min at 10.0 bar. This represents the total output of the Ulka at those pressures because the water has no other place to go other than the OPV relief. Keep in mind that these are average flow values of the pump production line so . . . a 5% (or more) tolerance can be applied.

The average flow going into the grouphead during brewing is 75 ml in 25 seconds which is 180 ml/min. This is taking into account the water flowing through the coffee grinds, the water which remains in the coffee grinds, and the water which filled the preinfusion chamber of the grouphead. The differential between 180 ml/min and whatever flow you have with a blind basket will flow from the spigot into the drip tray.

Hi Eric, thanks for your answer!

Second, during brewing, the priming valve should be shut. It is designed to close at 6-8 bar per the specs on the Ulka drawing I have.

Indeed there is a split second of no dripping inbetween the buildup from 2/4 bar upto 8/9 bar pressure. That is probably when the priming valve shuts and just before the OPV opens.

If your OPV is/was adjusted such that a 10.0 bar pressure produced a relief discharge from it (and it alone) of a steady drip, that is OK. If you put a blind basket in place and "brew", the steady-state flow into the drip tray would be 260 ml/min at 9.0 bar and 225 ml/min at 10.0 bar. This represents the total output of the Ulka at those pressures because the water has no other place to go other than the OPV relief. Keep in mind that these are average flow values of the pump production line so . . . a 5% (or more) tolerance can be applied.

If, by 'steady-state flow', you mean that I should measure the amount of water that comes out of the spigot once the pressure has build up to 10.0 bar then: yes, that's exactly what my machine does. If I start measuring from that 10.0 bar point for 10 seconds I get about 37 ml, so that's roughly 220 ml/min. Did I understand 'steady-state flow' correctly?

The average flow going into the grouphead during brewing is 75 ml in 25 seconds which is 180 ml/min. This is taking into account the water flowing through the coffee grinds, the water which remains in the coffee grinds, and the water which filled the preinfusion chamber of the grouphead.

Ok, so is that for a 18 grams (double) basket making 2 espressos of each 30ml in about 25 seconds, or is that an irrelevant question?

The differential between 180 ml/min and whatever flow you have with a blind basket will flow from the spigot into the drip tray.

Do you mean from the moment that the brewpressure is reached? With my machine that's after approx. 10 seconds, so in those remaining 15 seconds of the shot there should be coming 15*((220-180)/60) = 10ml (very roughly) out of the spigot? Did I understand correctly? I'm sorry for al these questions, just trying to figure out if I get it..

Thanks again.

That is probably when the priming valve shuts and just before the OPV opens.

That's actually tough to judge (although obviously you see something) because the discharge from the two devices I speak of are joined by a "tee" or a "y" and there is "x" inches of tubing to deal with. Its like shutting off the garden hose at the wall valve . . . the flow through the valve stops but the hose still has some water in it and thus continues to drain.

Did I understand 'steady-state flow' correctly?

Yes . . . but you could also let it run at "blind filter pressure" for 5-10 seconds and then measure the amount of liquid from the spigot in, say, 15 seconds. The longer you measure, the more accurate your number but remember that the pump has a rated duty cycle so give it a 1 or 2 minute break between experiments

. . . or is that an irrelevant question?

The question is not relevant. I was simply quoting the water amount from this:WBC Procedure for Measurement of Brewing Water Temperature - see Section 4.3 .

It is very worthwhile to measure the flow from an empty portafilter on a fully warmed up machine and with a full reservoir. Do it several times, average the results, and note it in your machine's manual. This could come in handy for future troubleshooting.