I have finally built a manometer attachment to the portafilter, but it is late here and I wanted to give it just a quick go on my Promac http://www.home-barista.com/espre...omatic-t10820.html I only opened a water to the machine, switched on (did not switch on the heating elements), put the portafilter in place, switched the "make the espresso" button, and nothing happened with the needle of the manometer. It did not move one bit.



I tried it with basket on, basket off, with valve opened (water flowing) and valve closed—no change.

Do you know where the problem could be? Should I just try to switch everything in the morning, including heating element? Will it make a difference?

Other questions:
1) the manometer is a glycerin one, is it normal that there is a big bubble of some gas in the liquid?
2) would it hurt the manometer if the measurements are made with a boiling water?

Thank you for the replies. I am trying to read the different topics here for an hour, but could not find an answer.

Vad wrote:...and nothing happened with the needle of the manometer. It did not move one bit.

Alex, I'll take "Things that Occlude" for $100.

Seriously now...

Vad wrote:Do you know where the problem could be? Should I just try to switch everything in the morning, including heating element? Will it make a difference? The manometer is a glycerin one, is it normal that there is a big bubble of some gas in the liquid? Would it hurt the manometer if the measurements are made with a boiling water?

A1. I assume the gauge orifice is blocked. A2. No. A3. No. A4. Yes. A5. No.

HB wrote:I assume the gauge orifice is blocked.

Thank you for your replies. That is odd. There is nothing I could think of, that could block the gauge orifice. I will unscrew it and have a look again.

EDIT 1: I have unscrewed the manometer, and the hole is clean. When I screwed it back in and put it into the machine, there was again nothing. Then I waited for 10 seconds, and finally it moved. But it stopped at 3.5 bars after like 2-3 seconds slow moving from zero and then the seal between the group and portafilter began to leak.



That is odd, because when I do backflushes, it does not leak. I have tried with basket, without basket, fixing the portafilter as strong as I could (pushing the handle to the right). Still leaks and I can't get above 3.5 bars.

What could be wrong now?

EDIT 2: I tried to put the rubber disk (as for backflush) in a basket with a DIY thingy, and it still leaks. But when it is in another basket—it does not (kept it under pressure for 20+ seconds). So I guess there could be a problem with the portafilter itself? I will try to screw my DIY portafilter gauge on another portafilter after I get home from work.

Or do you have any other ideas?

Vad wrote:...and then the seal between the group and portafilter began to leak.

Alex, I'll take "Things that Drip" for $200 (*).

Since there's no basket, the lock-in position will shift and the mating surface is smaller. If the grouphead gasket is old, it's more likely to leak. That said, it is not a reason for concern since drip drip drips while measuring pressure will not change the reading, especially on rotary pumps (they're readings are unaffected by flow rate since they're dramatically over-capacity).

(*) Sorry, another obscure Jeopardy! reference.

HB wrote:Since there's no basket, the lock-in position will shift and the mating surface is smaller. If the grouphead gasket is old, it's more likely to leak. That said, it is not a reason for concern since drip drip drips while measuring pressure will not change the reading, especially on rotary pumps (they're readings are unaffected by flow rate since they're dramatically over-capacity).

It is the same either with or without basket—drips anyway. The gasket rubber is 2 weeks new. So if I understand correctly, the measure I get is a correct one? 3.5 bars of pressure? The manometer is brand new. So should I trust it and increase the pump pressure? I wonder then, how was I able to prepare espressos with such a low pressure

Should I buy yet another manometer, to make sure this one is accurate? Or is there something in the design of my portafilter gauge (or the method I use it) that somehow shows me the results 2x-3x lower?

Hi Vad,

it might be leaking with the basket because the water goes through the basket hits the gauge and actually goes back up and finds it's way out underneath the basket where it touches the PF. When measuring pressure with a PF gauge I always remove the basket and stick a basket-less (yeah like that's a word) PF into the group making sure it sits tightly against the group gasket.

What pump does you machine have, rotary or vibe?

Regards,
dsc.

dsc wrote:it might be leaking with the basket because the water goes through the basket hits the gauge and actually goes back up and finds it's way out underneath the basket where it touches the PF. When measuring pressure with a PF gauge I always remove the basket and stick a basket-less (yeah like that's a word) PF into the group making sure it sits tightly against the group gasket.

What pump does you machine have, rotary or vibe?

I have tried both ways, with basket or without, the pressure on the manometer and the dripping is the same. I have a rotary pump, here is my machine http://www.home-barista.com/espre...omatic-t10820.html

I am starting to be clueless. I could try another portafilter when I get home, but as HB said, the dripping would not make difference pressure-wise. And 3.5 bars—is it something wrong with manometer and measurement technique/device, or the pump in a machine is set VERY low?

I would not make any adjustment to the pump until this pressure problem is resolved. What is the flowrate from the pump (ml/minute) when simply flushing?

Please describe the water hook-up to the espresso machine.

What is the normal pressure in your main supply line (house system)? You could always find an inexpensive gage and compare it with the PF gage you have testing the same source, i.e. house mains pressure.

erics wrote:What is the flowrate from the pump (ml/minute) when simply flushing?

It is about 60 ml in 10 seconds.

erics wrote:Please describe the water hook-up to the espresso machine.

Water outlet for a washing machine > flow restrictor > decalcifier > espresso machine. Should I measure the water pressure from the water outlet? Then from behind the water flow restrictor? (speaking simply the water from the wall outlet has a hell of a flow)

erics wrote:What is the normal pressure in your main supply line (house system)? You could always find an inexpensive gage and compare it with the PF gage you have testing the same source, i.e. house mains pressure.

I don't know what the pressure is. I will have somehow to connect the manometer from my DIY thingy to the water outlet (as I said in a previous paragraph).

What is the recommended bar pressure of a water flow into the machine (in my case what pressure should I have between the water flow restrictor)? So that I can setup it right and eliminate this variable.

Thank you all for your suggestions, I very much appreciate it.

By flow restrictor, I assume you mean pressure regulator and that should be downstream of the de-calcifier. Upstream of the de-calcifier, you should have some filtration device. A reasonable setting for the pressure regulator is 2.50 bar under flushing conditions but certainly I defer to a successful Rancilio owner or the mfg.

As the pressure regulator (flow restrictor) has a gage port, buy an inexpensive gage and screw it in. That port is designed to read pressure downstream of the regulation, i.e. my recommended 2.50 bar.

The flow of 60 ml in 10 seconds is on the low side. As a point of comparison, I have two vibe pump machines taking supply from their respective reservoirs and they both flow ~70 ml in 10 seconds.

As a first step, I would verify that the oil-filled gage and some inexpensive gage read similar values when connected to the same source. Maybe make a new friend at a local coffee bar and put your gage on their machine.

erics wrote:As the pressure regulator (flow restrictor) has a gage port, buy an inexpensive gage and screw it in. That port is designed to read pressure downstream of the regulation, i.e. my recommended 2.50 bar.

Here is a picture of a valve connected to the restrictor, as it was. In normal condition it showed 3.5 bar, and when I opened the flow, it showed 3 bar (the valve is small, so after flowing through a normal diameter tubing, it will show 2.5 bar, I guess).



Now I reduced it to 2.5 bar, so under flow it shows 2 bar. I am curious what will it change on the group. It is strange that the pressure was the same in the water way, as after the pump in the portafilter.

EDIT: I have now tried measuring the pressure in the group, and yes, it showed 2.5 bars—the pressure of water after the flow restrictor. Does it mean that there is something wrong with the pump, that it does not add to the pressure at all? When I change the pressure of water coming to the machine, the pressure in the portafilter precisely mimics it. It is the same!

erics wrote:The flow of 60 ml in 10 seconds is on the low side. As a point of comparison, I have two vibe pump machines taking supply from their respective reservoirs and they both flow ~70 ml in 10 seconds.

I now have digital scale, and will measure precisely how much water I get in 10 seconds.
EDIT: I have 56.6 ml of water in 10 seconds.

erics wrote:As a first step, I would verify that the oil-filled gage and some inexpensive gage read similar values when connected to the same source. Maybe make a new friend at a local coffee bar and put your gage on their machine.

I don't have any possibility of this, so I will maybe buy another manometer and compare. :-/

Does it mean that there is something wrong with the pump, that it does not add to the pressure at all?

Either the pump or the motor.

Why not check and see that the motor for the pump even runs? And does the pump turn freely when disconnected from the motor?

erics wrote:Either the pump or the motor. Why not check and see that the motor for the pump even runs? And does the pump turn freely when disconnected from the motor?

I am not quite sure as to how to do that. The pump is some model of this http://www.fluidotech.it/Pages/en_po_50_400.aspx So I have to unscrew it from the motor and then switch it on? Look at the motor whether it spins?



EDIT: I know that the previous owner used the machine without the water flow restrictor. If it helps somehow, to identify the source of the problem.

Other thing, the gasket now leaks slightly (drips and ocassionaly streams of drops), at the pressure of 2.5 bars. What would happen if the pressure is 9 bars as it should have been? I guess I think about too much (for two days now, trying to figure it out) and get lost in all of its details.

It looks like the question mark is pointing to a simple clamp. Loosen the screw and the pump should fall away from the motor. Then you can run the motor without the pump to see if it is working and turn the shaft on the pump by hand to see how it feels. Don't worry about disconnecting any water lines.

karmacafe wrote:It looks like the question mark is pointing to a simple clamp. Loosen the screw and the pump should fall away from the motor. Then you can run the motor without the pump to see if it is working and turn the shaft on the pump by hand to see how it feels. Don't worry about disconnecting any water lines.

Thank you for the quick reply. So I unscrew that clamp, disconnect the pump, and then press "make espresso" button? If the motor does not rotate—it means it is broken? Or there is some rate at which it should normally rotate and I will be able to see a deviation from that normality?

And then I should test another thing as you suggest, switch the "make espresso" button off, and try to rotate the pump by hand—what should I expect from that, what would it say to me?

Thank you also about water lines information, that worried me too. Now I will be calm about it, that water will not run through the internals.

Can you simplify that gauge apparatus? Can you connect the gauge right below the portafilter instead of with that T setup? It is hard to believe you are only getting 3.5 bar.

My cheapie air pressure gauge does take about 10 seconds to reach a full pressure reading.

2 sweaner: But it shows the same measurements in pressure of water coming into machine, and the water coming out of the machine. And that does not depend on the design of the gauge, I would say. :-/ I am now searching for a second manometer, to verify the results of the first one.

EDIT 1: I have been talking to a hydraulics expert now, and showed him my DIY setup. He said that the design is not bad, and can not lead to significant misreadings.

EDIT 2: I have now bought two more different manometers, just to be sure that the pressure is what it is.

Here are the pics of a motor and pump combo disassembled. There is some strange stuff there, kind of an oxidation. I tried to rotate the pump by hand, and it is kind of stuck in the beginning, I have to turn harder, and then it spins ok. But when I stop rotating it, it is again difficult to start rotating it. i.e.: not a silky smooth action.

When I hit the "make espresso" button, the motor spins, but the pump thingy does not. But the water comes out of the group.

What do you make of it?

Is this what you are calling the "pump thingy" ?

That is an extension of the electric motor's rotor which drives the pump. If that does not rotate when you press "make espresso", the motor shaft has been sheared thanks to corrosion from a leaking pump seal.

So, if what I said above is true, you need a new motor and a new/rebuilt pump