La Pavoni 1974 single switch - Page 2

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rpavlis
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Joined: Jan 08, 2012, 3:26 pm

Postby rpavlis » May 07, 2016, 10:54 am

There is a space between the group wall and the cylinder liner that becomes filled with water during operation of both first and third generation La Pavoni levers. If one move the handle up and down it brings water from the boiler into and out of the space, heating it up. If one fail to do this, the group temperature will be low for a long time--until it heats by conductance, something that takes a relatively long time. If one pump it up and down too much it will get it too hot. If should only do this, in general before the first shot.

(2nd generation machines do not have this system, live steam is constantly heating the group by condensing above the piston at the top of the group. There is a small hole to admit steam from the boiler.)

18g
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Joined: Sep 21, 2015, 6:33 pm

Postby 18g » May 07, 2016, 7:33 pm

crazy4espresso wrote:Congrats on the machine. I haven't looked at the 1974 manual, but if it's anything like many other Italian manuals for lever espresso machines, they basically say "Pull once for single shot, pull twice for a double"; pretty vague and essentially useless. Your best source of information on these machines is right here, and DrGary and rpavlis have posted more on these machines than anyone else on this forum, I suspect. Start reading! :D
There is a wealth of information here. Welcome!


I'm reading so much, my eyes are bleading. Thank you for the welcome.

drgary wrote:The shower screen is removed by removing the portafilter gasket, which holds it in place. The volume of shots has little to do with the switch positions as long as the machine is up to pressure. If you're getting low volume, it is probably because you are insufficiently bleeding air out of the machine before the first shot. See:

Bleeding pressurestat lever machines. (Especially 2nd gen La Pavonis)

Or, if you have a 220v machine plugged into 120v power could be low, or, if the high heating element is burnt out, you may not be getting full heat on warmup so there's insufficient pressure. When you first power up on high you should get vigorous steam release at the safety valve at the upper right, and then turn it down. That's the position for warmup and steaming.


Do you think I can remove the portafilter gasket, clean behind the shower screen and put the gasket back or will I need replacement gasket? My machine is in very good conditon and don't think it's been used much, so feel a little uneasy to remove the gasket.

I don't think my machine has a pressurestat, there is no copper pipe under the base? Should I still bleed air out of the machine?
I turn on machine on hi setting, after 7min 20s there comes few drops of water out of safety pipe and after 7min 50s steam comes vigorously through safety valve. With 14-15g dose I get max 24g output with single pull and stock basket. How much output should I be able to get with this setup? So far only low volume and bad tasting shots but I am anyway in love with this lever and hope things get better with practise so I can retire the Silvia.

rpavlis wrote:There is a space between the group wall and the cylinder liner that becomes filled with water during operation of both first and third generation La Pavoni levers. If one move the handle up and down it brings water from the boiler into and out of the space, heating it up. If one fail to do this, the group temperature will be low for a long time--until it heats by conductance, something that takes a relatively long time. If one pump it up and down too much it will get it too hot. If should only do this, in general before the first shot.

(2nd generation machines do not have this system, live steam is constantly heating the group by condensing above the piston at the top of the group. There is a small hole to admit steam from the boiler.)


Thank you!

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drgary
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Postby drgary » May 07, 2016, 8:28 pm

"Do you think I can remove the portafilter gasket, clean behind the shower screen and put the gasket back or will I need replacement gasket? My machine is in very good conditon and don't think it's been used much, so feel a little uneasy to remove the gasket."

You'll need to remove the gasket from time to time to service the machine. If it's still flexible you should be able to gently pry it out. If not it's probably worth getting a couple so you have replacements on hand.

"I don't think my machine has a pressurestat, there is no copper pipe under the base? Should I still bleed air out of the machine?"

No pressurestat, but that's perfectly OK. I have one where I installed a modern heating element with pressurestat and two that I restored with the old two element heating system. I like the old style as much as the new.

"I turn on machine on hi setting, after 7min 20s there comes few drops of water out of safety pipe and after 7min 50s steam comes vigorously through safety valve."

That's exactly as it should be.

"With 14-15g dose I get max 24g output with single pull and stock basket. How much output should I be able to get with this setup? So far only low volume and bad tasting shots but I am anyway in love with this lever and hope things get better with practise so I can retire the Silvia."

You need an excellent grinder to properly control a pressurized manual lever machine. Beyond that it's practice, practice, practice. The coffee cake is the brakes of this car. With the mediocre shots you might learn to enjoy milk drinks while improving technique. The truly bad shots of course go into the sink. After awhile you may not need to measure anything and the shots will be consistently good. With new coffees you may take a couple of shots to dial in and the others go to milk drinks. At least that's where I am these days.

If you're not familiar with it we on Team HB consider the following required reading for this site. If your eyes are bleeding it can wait until at least tomorrow morning. :wink:

Espresso 101: How to Adjust Dose and Grind Setting by Taste
Gary
LMWDP#308

What I WOULD do for a good cup of coffee!

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rpavlis
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Joined: Jan 08, 2012, 3:26 pm

Postby rpavlis » May 07, 2016, 8:35 pm

None of the first generation machines had pressurestats. The pressure relief valve systems basically self bleed the boiler space, and if you move the handle up and down after steam is escaping it will tend to clear air out of the group.

Again, when I use my first gen machine I power it up with both heating elements on, and when it starts to hiss I put something under the group like a Ramekin and quickly move the lever for the least possible time up to release as little as water as possible and then bring it down again. Then I make three "pumps" but not moving the handle far enough to release any steam each time. In a cold ambient temperature I am apt to do four pumps. Each pump action brings hot water into and then out of the space between the cylinder liner and the group walls to get it heated. Otherwise the group will be too cold. (Some system for measuring the temperature of the side of the group is a good idea here at least until you have parameters mastered. I like ir thermometers, you need to put a piece of tape on the side of the group to that.) If you pump it up and down too much it can become too hot.

After this I turn off the high element and immediately make the shot which I have prepared whilst the machine was heating. These machines are much less tricky than second generation machines, and they have far better "build" quality than third generation ones. In my opinion La Pavoni should have improved on these rather than go off in other directions as they did in both the second and third generation machines. They apparently did not believe in the idea, that if it be not broken, do not fix it!

18g
Posts: 12
Joined: Sep 21, 2015, 6:33 pm

Postby 18g » May 12, 2016, 4:57 am

rpavlis wrote:None of the first generation machines had pressurestats. The pressure relief valve systems basically self bleed the boiler space, and if you move the handle up and down after steam is escaping it will tend to clear air out of the group.

Again, when I use my first gen machine I power it up with both heating elements on, and when it starts to hiss I put something under the group like a Ramekin and quickly move the lever for the least possible time up to release as little as water as possible and then bring it down again. Then I make three "pumps" but not moving the handle far enough to release any steam each time. In a cold ambient temperature I am apt to do four pumps. Each pump action brings hot water into and then out of the space between the cylinder liner and the group walls to get it heated. Otherwise the group will be too cold. (Some system for measuring the temperature of the side of the group is a good idea here at least until you have parameters mastered. I like ir thermometers, you need to put a piece of tape on the side of the group to that.) If you pump it up and down too much it can become too hot.

After this I turn off the high element and immediately make the shot which I have prepared whilst the machine was heating. These machines are much less tricky than second generation machines, and they have far better "build" quality than third generation ones. In my opinion La Pavoni should have improved on these rather than go off in other directions as they did in both the second and third generation machines. They apparently did not believe in the idea, that if it be not broken, do not fix it!


Just made 2 shots following your method and finally got both shots over 30g :D . After doing the quick three pumps, the group temp was only 60c so I just waited, maybe 3 more minutes and then pulled the shot. When I pulled the shot, the group temp was at 80c. The shot was much hotter than my shots on the Silvia and I didn't really like it. Did you forget to add the step with the late lockin or is that no good for my model? Would it matter if I turn off the high setting before the three quick pumps instead? Tried a lot of different methods yesterday and nothing really worked but maybe those 3 quick pumps was the missing part. Thanks for the receipe!

1. Turn on High setting.
2. When hissing starts, switch to Low setting.
3. Raise lever to remove small amount of water. Bring down lever.
4. Make 3 quick pumps without releasing any steam.
5. Make the shot when group is at 75-90c
6. Late lockin

Scott6468
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Joined: Jan 21, 2015, 12:08 pm

Postby Scott6468 » May 12, 2016, 8:12 am

Robert,

Thank you for posting your method. Is the prepared portafilter and basket at room temperature when you lock it in?

Scott

 
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