Getting started with the Vibiemme DoubleDomo Super - Page 2

[networkcrasher]

You have two boilers. The steam boiler has no connection with the 3way discharge.
The pump and brew boiler are connected to the group. The discharge is to release pressure on top of the puck so as you don't get sprayed when you take the portafilter out.
The steam boiler is connected to the steam valve and wand.

My question would be, as there is a pressurestat, if it is only for the steam boiler and why would you take a big, expensive Sirai when steam temperature might not be as critical as espresso temperature. Does the non-PID version have two pressurestats then, one for the steam boiler (Sirai?) and the other for the brew boiler?
Another interesting thing is how the brew boiler maintains group temperature. There must be a loop from the brew boiler into the group and back. But does it include a HX?


Regards
Peter
Netherlands
Europe

Whoops, there should have been an 's' after thing.. as in The only weird things I've noticed are the steam pressure being at 1.5bar; and the brew pressure gauge stays at pressure even after the PF has been removed. I'm well aware it has two boilers

The non-PID version is a HX.

From what I can see by looking inside, there is a loop going to the group. Well, let's put it this way, there are two copper pipes going to the group.

[CaffeRoma]

I got mine about a month ago, but have not really had the time to fully delve into the details of the machine. With the many questions I'm sure we will all be sharing in the next few months, the one thing that I have noticed is that the steam pressure (pre-set to 1.5 bar) drops off to 0.5 and then zero pretty quickly. I can really only steam single cappuccino amounts of milk maintaining a 1 - 1.5 pressure level. If I try to do two latte's at once it is takes much too long and the steam pressure is at zero for the latter part of the process.
Anyone else experiencing this? Should I be adjusting the steam pressure-stat for this?
THANKS!

[networkcrasher]

If I try to do two latte's at once it is takes much too long and the steam pressure is at zero for the latter part of the process.
Anyone else experiencing this? Should I be adjusting the steam pressure-stat for this?
THANKS!

I have the exact same issue. It's almost as if the boilers are backwards.

[cafeIKE]

Clarification : The DUAL Boiler version has a PID for the BREW boiler and a pstat for the steam boiler. The brew boiler feeds the group via a thermosyphon and the BREW* boiler water makes the coffee.

The SINGLE boiler version is an HX and has ONE pstat.

[*edit : thanks, zin1953 ]

[zin1953]

Clarification : The DUAL Boiler version has a PID for the BREW boiler and a pstat for the steam boiler. The brew boiler feeds the group via a thermosyphon and the boiler water makes the coffee.

Boiler water from the BREW boiler, one presumes.

[zin1953]

I got mine about a month ago, but have not really had the time to fully delve into the details of the machine. With the many questions I'm sure we will all be sharing in the next few months, the one thing that I have noticed is that the steam pressure (pre-set to 1.5 bar) drops off to 0.5 and then zero pretty quickly. I can really only steam single cappuccino amounts of milk maintaining a 1 - 1.5 pressure level. If I try to do two latte's at once it is takes much too long and the steam pressure is at zero for the latter part of the process.
Anyone else experiencing this? Should I be adjusting the steam pressure-stat for this?
THANKS!

I have the exact same issue. It's almost as if the boilers are backwards.

OK, this could be a potentially serious flaw . . . regardless of whether the boilers are "backwards" or not, if you can't steam milk for lattes back-to-back without the pressure going to zero . . .

Me thinks this is not a good thing.

[seattlesetters]

OK, this could be a potentially serious flaw . . . regardless of whether the boilers are "backwards" or not, if you can't steam milk for lattes back-to-back without the pressure going to zero . . .

Me thinks this is not a good thing.

And would negate my top reason for having dual boilers in the first place (to have excellent, simultaneous steaming power while maintaining solid, easily repeatable, known temperatures for brewing).

[networkcrasher]

Can anyone give a good reason why the brew boiler is twice the size of the steam boiler? What benefit does one gain by having such a large brew boiler? Wouldn't recovery time be short from shot to shot if the brew boiler is smaller? That's the philosophy the S1 took.

[cafeIKE]

Can anyone give a good reason why the brew boiler is twice the size of the steam boiler? What benefit does one gain by having such a large brew boiler? Wouldn't recovery time be short from shot to shot if the brew boiler is smaller? That's the philosophy the S1 took.

The recovery time is based on the input power, the inlet water temperature and volume. A larger boiler should give a more stable temperature over the shot, if the water injection is well managed.

[seattlesetters]

However, the smallish .75l boiler of the Quick Mill Alexia has delivered some of the most stable shot-to-shot temperatures ever recorded on The Bench at H-B.

[gadflea]

I have the exact same issue. It's almost as if the boilers are backwards.

This is interesting because the spec's now listed on Stefano's Espresso Care website say that the brew boiler is .7L and the steam boiler is 1.4L. http://www.espressocare.com/VibiemmeMainWithPID.html This would suggest that the boilers are indeed switched. I cannot imagine Vibiemme making such a mistake. I am inclined to think the specs given are wrong, but who knows?

[networkcrasher]

This is interesting because the spec's now listed on Stefano's Espresso Care website say that the brew boiler is .7L and the steam boiler is 1.4L. http://www.espressocare.com/VibiemmeMainWithPID.html This would suggest that the boilers are indeed switched. I cannot imagine Vibiemme making such a mistake. I am inclined to think the specs given are wrong, but who knows?

Without seeing one, I'd think that the brew boiler was the smaller of the two, but I can guarantee that the brew boiler is MUCH larger!

[CafSuperCharged]

Copying myself from
opinions-sought-elektra-t1-vs-cimbali-junior-dt1-vs-vibiemme-doubledomo-super-t6728.html#p79846

The initial response proves again, you should not decide based on specs (or maybe you should?)

Reading into the specs as they seep through, I would say, one BIG HX boiler was replaced by a small brew boiler and small steam boiler. [This] forum did not decide which of the two small ones is petite.
Initial response [here], you could do one or two cappuccinos and the steam pressure drops too much for the next one.

If you go back to the specs: the machine was built starting with a large water tank and for space reasons a vibration pump. Next they fitted in two boilers. Necessarily smaller than the single big one in the Super.
Subsequently, they did a plumb in version where the water tank is replace by a rotary pump (and a lot of space - liters - remains unused).

The steam insufficiency reported by two users new to the machine, it may prove the design is very stable for espresso, but does not deliver infinite amounts of steam.
BTW. Could it be the US imports a 110V version that has less Watts power in the steam boiler in order to stay under the 15A you from over there mention a lot? And a 220V version would just have more Watts to keep the steam boiler under pressure for whatever amounts of steam? If so, this is a serious design issue with an Italian company that probably designed this machine with the US market in mind first.

Regards
Peter
Netherlands
Europe

[zin1953]

Agreed, Peter . . .

[CafSuperCharged]

Have you noticed the other discussion:
new-vibiemme-doubledomo-owners-read-this-before-turning-unit-on-t6752.html

This is about the first time use procedure for the VBM DS DB. Apparently they forgot to timely/properly relay instructions on first time use (how to prime the machine).

Electrical heating elements in espresso machines can run too hot, apparently, when switched on in an empty boiler.
That's why you need to step-by-step switch your HX machine on/off so the heating element can cool down sufficiently as the boiler will be filled until the level detector decides it is completely filled.
In this case there are two boilers: one steam that needs to be filled and which has a level detector to top it up. This would require a similar procedure, unless there is a switch on the machine (as found on some VBM's) that switches the boiler fill system when the heating cannot switch on.
In the case of the DB machine this still leaves the brew boiler to be filled, as I understand it. And the brew boiler we should consider as a very thick section in the water tube between the pump and the group. It must be completely filled before the heating is switched on (PID version). In a non-PID version I would assume a either a switch for pump only, or a procedure to be followed.
So far, so good.

Now back to topic. What if the procedure is not followed and the heating element gets overheated, however does not break? Could it be it loses its power partly? I hope you new users of this enormously anticipated machine did not run into these pitfalls, but feel it must be excluded from the list of hypotheses before the design is discarded (as I implied above).

Regards
Peter
Netherlands
Europe

[networkcrasher]

Well, given the fact I wouldn't know but only one side of that question, it's hard to say if it loses power or not. For instance, if my boiler is not operating normally and the element is not fine, how would I distinguish that from a properly heating boiler/element? Status quo is what I'm used to from the day I fire up the machine.

There are basically 3 switches on the machine. position 1 primes the steam boiler. I'm not sure if it primes both or not, but it sounds like it just primes the steam boiler, otherwise there wouldn't be an issue with the brew boiler not having any water in it if position one primes it as well. Stefano seems to have confirmed this by stating the brew boiler is filled via displacement only when pulling a shot. Position 2 turns the machine on (I think anyway). The 3rd (but different button) turns on the PID. What I'm confused about is when the actual elements are on. If the elements are supposed to be on in position 2, but the PID is off, what is controlling the elements?

My thoughts are position 2 is that it only controls the steaming element and position 1 can be combined with the PID to turn on the brew boiler. That's what it sounds like from the post Stefano made.

[CaffeRoma]

What if the procedure is not followed and the heating element gets overheated, however does not break? Could it be it loses its power partly? I hope you new users of this enormously anticipated machine did not run into these pitfalls, but feel it must be excluded from the list of hypotheses before the design is discarded (as I implied above).

I think you have a good point there Peter.... I did not know of these instructions when i first got my machine - in fact there is no mention of this anywhere - as many of you know the instruction manual that is supplied by VBM is completely inadequate.

I hope that your point is not the case - however I am not sure how we can verify this? Anyone?

Cheers,
Andrea

[CafSuperCharged]

[...] position 1 primes the steam boiler. I'm not sure if it primes both or not, but it sounds like it just primes the steam boiler, otherwise there wouldn't be an issue with the brew boiler not having any water in it if position one primes it as well. Stefano seems to have confirmed this by stating the brew boiler is filled via displacement only when pulling a shot. Position 2 turns the machine on (I think anyway). The 3rd (but different button) turns on the PID. What I'm confused about is when the actual elements are on. If the elements are supposed to be on in position 2, but the PID is off, what is controlling the elements?

My thoughts are position 2 is that it only controls the steaming element and position 1 can be combined with the PID to turn on the brew boiler. That's what it sounds like from the post Stefano made.

From brief scattered descriptive statements I would deduce that the brew boiler is not like a HX steam boiler, but physically like a very wide section in the tube from the pump to the group. This means it will only fill when the pump is switched on to make espresso. Once water came out of the group, this (brew) boiler would be filled. The boiler and tubing would have to be designed/engineered in a way that avoids air to be trapped inside.
In the PID version, the heater in the brew boiler is controlled by the PID, so it should be very easy to fill the brew boiler by opening the brew group (switching the brew pump on) until water comes out WHILST the PID is off (or set to zero something degrees for the brew boiler).
Question is how to proceed with the non-PID version. I assume there is only one pump and the brew pump will be on a 3-way valve that opens to top-up the steam boiler. It might be possible, once the steam boiler is full - position 1 of the power switch - to open the brew valve (switching the pump on) and let the machine pump until water comes out of the group. Now switch to heating position.

I am not sure if the power switch has this prime (steam boiler fill) position, and this position was used why we would have to try and reject a damaged steam heating element hypothesis. That hypothesis could more likely apply to the brew boiler heating element, given the lack of clarity as to the fill procedure.

Regards
Peter
Netherlands
Europe

[CafSuperCharged]

Wouldn't it be nice to have a separate 3 position on/off switch for the steam boiler? With its own simple vibe pump? So the accidental automatic topping up of the steam boiler would not ruin your espresso? I can even imagine the steam pressurestat could be replaced by a simple digital thermostat (the kind in the brewtus), or the pressurestat could remain in line with the thermostat switching the heating element so as to have an adjustable pressure maximum.
The switch and digital thermostat would add some cost, however during longer episodes of real coffee only, the steam boiler could be left off . A simple vibe pump might be as expensive as the 3-way (water feed/steam boiler/group) valve plus additional tubing (labor) involved in the single pump design. So the added total cost should be limited.

Regards
Peter
Netherlands
Europe

[ira]

I can even imagine the steam pressurestat could be replaced by a simple digital thermostat (the kind in the brewtus)

If you use a thermostat for the steam boiler the heating element won't likely turn on the instant you open the steam valve and you might find the steaming abilities slightly reduced.

Ira