The Carezza compendium

[Tex]

The Silvia wand mod is external only. There is nothing involved that takes more than an adjustable wrench and maybe a bit of sandpaper. Piece of cake!

Cool, you might generate some Silvia wand sales with this one..I am shopping in another tab for one right now. 

How does it come out?

Does removing those Allen bolts allow the wand connection to drop down outside the jacket?

I'm guessing that nut visible on the steam wand needs to come off but it is up inside the jacket so I can't figure how to put a wrench on it without opening up the machine.

I know you are the Gaggia guy so I defer to your expertise...how do we get this thing out without opening up the machine?

 

Looks like someone's already been improving your Carezza? The point where the wand connects to the pipe is supposed to extend through the case. It looks like someone has bent the tube on yours. I was looking for a picture that shows this, but I've never shot one from that angle.

So, in your case it probably would be necessary to pop the top to get at the wand. I'd be curious if you can tug the wand back into position?

I've been buying my wands here, but I see they're out of stock.

I'm attaching an exploded parts diagram for the Carezza that should help you.

[staylor]

Bummer, you already have a collection of tips, you should put them in the tip jar - groan. ;-)

I hope it works out for you, just try to understretch the milk initially, literally. Put the tip on the surface and only stretch the milk for like 2-3 secs, and even though you "know" that is a ridiculously short period of time and you "know" it didn't stretch enough... just go with it and get on with sinking that wand and smashing those bubbles. If the milk isn't capable of pouring art then start again and add another second of stretch to the initial phase and then sink the wand in and begin the bubble-smash again, if that pour didn't work then add another 1sec of strech, etc.

You'll get it. But if you have questions, fire away.

Actually ... I do have a question for you.  when you set the pressure to steam ... how far past the steam turn on point do you turn the knob? 

I find that if I put to much oomph into the steam output it severely shortens the time you can have the tip in the milk before the milk over heats.  Do you find that too or am I off in left field on this one?

Thanks

It's a good question and it really depends on the machine. Some boilers/steamwands/tips have a lot of "oomph" whereas others are a bit limp-wristed. Further to that, it depends on how much time you have on your wand, how used to using it. I can open my and all the way up and get right at it, but there is no harm in opening up your wand to 50% steaming force, setting up the surface skim bubble introduction and then sinking the wand going to 100% steaming force and smashing those bubbles up.

Remember, nearly 99% of my milk drinks are done steaming only 2ozs of milk. You have to have a good eye for the milk, a good understanding of manipulation and a very good understanding of temp bandwidth to time relationship. IF I open the wand to 100% I can miss the optimum microfoam by just a couple of seconds. The upside is if I miss the optimum point the non-optimal microfoam still kicks regular hot milk's asssssss. Microfoam can take even mediocre espresso and transport it in such a fashion that it's drinkable.

There's nothing worse than hot dead milk. Keep at it, you'll be glad you did.

[John F]

So, in your case it probably would be necessary to pop the top to get at the wand.

After looking at it a while I decided the same thing and opened it up.

I'm thinking now about removing it up top on the brass section and working at it with the entire wand out in the open rather than trying to wrench around in the tight space of the machine.

I took the opportunity to get a few pics of the inside that I will add to the top 2 posts later on but here is the connection I think I'll go after to do the swap.

[mp]

It's a good question and it really depends on the machine. Some boilers/steamwands/tips have a lot of "oomph" whereas others are a bit limp-wristed. Further to that, it depends on how much time you have on your wand, how used to using it. I can open my and all the way up and get right at it, but there is no harm in opening up your wand to 50% steaming force, setting up the surface skim bubble introduction and then sinking the wand going to 100% steaming force and smashing those bubbles up.

Remember, nearly 99% of my milk drinks are done steaming only 2ozs of milk. You have to have a good eye for the milk, a good understanding of manipulation and a very good understanding of temp bandwidth to time relationship. IF I open the wand to 100% I can miss the optimum microfoam by just a couple of seconds. The upside is if I miss the optimum point the non-optimal microfoam still kicks regular hot milk's asssssss. Microfoam can take even mediocre espresso and transport it in such a fashion that it's drinkable.

There's nothing worse than hot dead milk. Keep at it, you'll be glad you did.

Thanks Shaun.

I will continue to experiment to establish best microfoam production.

 

[Tex]

So, in your case it probably would be necessary to pop the top to get at the wand.

After looking at it a while I decided the same thing and opened it up.

Two things;
1) Take a look at the attached file and see if your SPV is working correctly.
2) I'd bend the tube down so the wand fitting is positioned below the case. At some point you'll want to remove it for cleaning.

[John F]

At some point you'll want to remove it for cleaning.

Man...out of sight out of mind. I'm cleaning that section during descale. 

It was fun looking inside the machine. What is this thing a pressure stat?

It's got an adjustment slot on the end of it accessible from the outside....I wish it was an OPV..I didn't' even know it was in there whatever it is, this machine has never been open. 

[Tex]

... whatever it is, this machine has never been open. 

Then this was an eye-opening as well as a machine-opening experience for you! Ever since my Aggie days, as soon as I get anything I start tearing it apart to see what makes it tick & how it can be improved.

There are no pstats in Gaggia's. The self-priming-valve (SPV) is Gaggia's miscarried attempt to dumb down some of their machines. They figured the typical noob wouldn't be able to figure out how to prime a boiler so they came up with this brain-fart.

Supposedly, it permits air to escape from the boiler during startup, preventing air locks. Then, once the boiler is full, a pea-valve is supposed to close, stopping hot water & steam from venting into the water reservoir. Guess what? THEY DON"T WORK!

I once had a handful of new Carezza's that a friend bought as Christmas gifts for selected employees. He asked me to check them out and install PID's & OPV's. While testing I left each machine on & idle for a couple of hours, and the water in each machine's reservoir reached ~160?F. I was concerned because the Ulka pumps have a maximum temp rating of 50?C - I saw the possibility of premature pump failure at these temps.

When I asked Gaggia about it they replied that it was a tried & tested design and that they were happy with it. That's when I decided to come up with a mod to correct the problem myself. The file I attached to an earlier post was the result of that effort, and I'm happy to report that it's become one of the most common mods made to Gaggia home espresso machines.

[Tex]

It was fun looking inside the machine. What is this thing a pressure stat?

It's got an adjustment slot on the end of it accessible from the outside....I wish it was an OPV..I didn't' even know it was in there whatever it is, this machine has never been open. 

That's the hi-pressure valve (similar to a pop-off valve on commercial machines). Gaggia says they're adjustable but they're full of hooey!

Gaggia does make an adjustable OPV for your boiler (shown below). It's a simple bolt in replacement for the OEM water inlet fitting (#36 in the parts drawing). They cost about $40 (+S&H) and they're well worth the effort & expense.

Without an adjustable OPV, the group pressure is going to be whatever the pump is capable of (~14 bar). That's too high for espresso but an adjustable OPV lets you reduce that to the recommended 9 bar. This one mod alone will dramatically increase the amount & quality of crema.

[John F]

That's the hi-pressure valve (similar to a pop-off valve on commercial machines). Gaggia says they're adjustable but they're full of hooey!

It's interesting...

Why are they full of hooey I have to ask because it does have an adjustment on it that looks like some other OPV's I've seen before. I'm wondering what adjusting it would do.

[Tex]

That's the hi-pressure valve (similar to a pop-off valve on commercial machines). Gaggia says they're adjustable but they're full of hooey!

It's interesting...

Why are they full of hooey I have to ask because it does have an adjustment on it that looks like some other OPV's I've seen before. I'm wondering what adjusting it would do.

The adjustments won't hold in that valve. Five minutes after you've spent an hour getting it close to 9 bar it'll jump up to 12 bar or down to 6 bar. It's useful to protect against excessive pressure but it's worthless when it comes to regulating group pressure.

[John F]

Without an adjustable OPV, the group pressure is going to be whatever the pump is capable of (~14 bar). That's too high for espresso but an adjustable OPV lets you reduce that to the recommended 9 bar. This one mod alone will dramatically increase the amount & quality of crema.

I don't have a crema deficiency but I am wondering about pressure at the pump vs pressure at the puck. I was reading something a while back about Gaggia loosing pressure at the pea valve so even at 14 bar some is going to be dumped by passing the pea valve. They were actually concerned about loosing too much pressure and being under 9 bar IIRC.

If I add an OPV and kill the SPV is there any way to deal with the pea valve (do you know about this issue)?

Of course without any of these mods you make adjustments for these things at the grind/tamp to the best effect for the shots....but making better output a the machine would be preferable. I'm guessing if I made improvements at the machine I'd re-adjust on my end for improved shots but a dramatic increase in crema  would not be my focus.

[Tex]

I don't have a crema deficiency but I am wondering about pressure at the pump vs pressure at the puck. I was reading something a while back about Gaggia loosing pressure at the pea valve so even at 14 bar some is going to be dumped by passing the pea valve. They were actually concerned about loosing too much pressure and being under 9 bar IIRC.

If I add an OPV and kill the SPV is there any way to deal with the pea valve (do you know about this issue)?

Of course without any of these mods you make adjustments for these things at the grind/tamp to the best effect for the shots....but making better output a the machine would be preferable. I'm guessing if I made improvements at the machine I'd re-adjust on my end for improved shots but a dramatic increase in crema  would not be my focus.

No, you're not short on crema!  But you probably would notice a slight improvement if you added a few mods to your Carezza.

Are you referring to the "pea-valve" in the group valve or in the self-priming-valve? The group valve is seldom a problem so I'll assume you mean the SPV. The mod I developed eliminates the SPV altogether; trust me, it's not a loss at all.

When the SPV leaks hot water & steam back into the reservoir, it can dramatically affect group/brew pressure and steam capacity. There was no point in trying to maintain a proper brew pressure when an indeterminate amount of pressurized water was being bled away through the #%!*ing SPV! It was worse with steam pressure - you could be reduced to a mere trickle of steam as the water in the reservoir was being heated to 160?F and above. The removal of the SPV in the steam valve and replacing it with a 1/16 NPT brass pipe plug solves all that.

You can make adjustments for an improperly tuned espresso machine, just like you can for an improperly tuned car. But are you getting everything from those beans that you paid for, or are you tossing the good stuff in the trash like you pump good hydrocarbons out the tailpipe of the car?

 :icon_bigsmurf:

[John F]

Are you referring to the "pea-valve" in the group valve or in the self-priming-valve?

The group valve.

They were saying at brewing pressure the valve is opened and it bleeds off pressure (away from the puck). Effect is that you never really get 12bar at the puck because at whatever point the spring holding the pea valve closed is overcome and pressure is lost.

I don't know.....I just read it is all. 

[Tex]

Are you referring to the "pea-valve" in the group valve or in the self-priming-valve?

The group valve.

They were saying at brewing pressure the valve is opened and it bleeds off pressure (away from the puck). Effect is that you never really get 12bar at the puck because at whatever point the spring holding the pea valve closed is overcome and pressure is lost.

I don't know.....I just read it is all. 

The group valve is rated at ~1.2 bar. It's a one-way valve and when the shot is being pulled it's completely opened and has no impact on group pressure. It's purpose is to prevent coffee being backflushed into the boiler when the shot is finished and to reduce the leakage at the group head of water & steam when they're pulled through the steam wand. The valve often leaks pretty bad so I suggest folks put a small cup or glass under the group when pulling water & steaming. Some folks use a blank backflushing disk to stop the leaking.

When you do preventive maintenance of the shower screen & holder, you should remove the group  valve also, disassemble it, and soak it in a citric acid solution to remove mineral deposits. This will permit the valve to close completely and stop the coffee in the group head from entering the boiler. You should never try to backflush a machine with a group valve; doing so could cause the alkaline detergent into the boiler and damage the aluminum.

And if you want to know what the group pressure is a simple portafilter pressure gauge can be assembled from Ace Hardware parts for ~$16.

[John F]

The group valve is rated at ~1.2 bar. It's a one-way valve and when the shot is being pulled it's completely opened and has no impact on group pressure.

Yeah, I see what you are saying.....I don't know what those guys were looking at.

Now I see why the SPV is the weak link.

So tell me this, what happens when you defeat it as far as potential harm to the boiler. I always pull water from the steam wand upon start up anyway so I am not concerned with that as much as somebody bumping the machine, or playing around with it and pull/no prime when I'm not home. Can you ruin the boiler, run it dry, or cause any damage air locking it?