I successfully added a pressure gauge to my europiccola

[bobby yarrow]

I know there's some speculation as to whether it can be done or not, and I guess the general consensus was that it could be done to older 2-button machines, but even then there was some uncertainty.

I have a 20 year old 2-button machine. With a $7 gauge (actual cost from La Pav, $50) and a $1 nut (actual cost from La Pav, $18), the gauge went right on. Actually, you have to disassemble to gauge to get it on, but only because the body of the unit is too close to the stem to let you screw the gauge on fully assembled.

La Pav sure knows how to mark up parts prices. I don't know if it was worth the $68 I paid for $8 worth of parts, but I can at least confirm that it works.

[j7on]

Ok, but have anybody added a pressure gauge that would actually be useful...?

That is, to the grouphead!
I have been playing around with this thought for quite some time and why not, it could be done, you could drill a small hole on the lower end of the grouphead so that it would come inside directly over the showerscreen, then thread it from the outside and screw in a pressuregauge(one that holds water), this way you could always check what pressure you are giving the coffee.

Anyone tried this yet?

[bobby yarrow]

Yeah, 'reversability' is kind of a touchstone for me. I AM curious about what pressure I'm actually getting at the screen, and I'm darn sure it varies a lot -- if I misjudge the grind, or the distribution, or the tamp, I can get shots where I can press the lever comfortably without even holding onto the machine, or other shots where I practically have to stand on the lever to get a pull. I know what my personal target is -- my ideal pull requires a hand on the pressure valve and the lever right up under my shoulder, starts with dribble of thick black, and then turns quickly to all crema, requiring consistent pressure through the full pull. My ideal pull takes about 30 seconds and produces about an ounce and a half of coffee once it's settled. But for one thing, that's just my taste -- a lot of folks really don't care for it -- and for another, it's hard to duplicate reliably.

[Ritske]

Hi Bobby,

I have the same 2-button Europiccola, and like you I would like to fit it with a pressure gauge. Could you give me a little more info about what gauge you used? I've been shopping around for non-pavoni gauges, but I got the impression that cheaper models usually can't handle being in contact with steam. At least, that's what a shop here in the UK told me. I was looking at this (cheap, general purpose) gauge:

http://www.pressuregauge.co.uk/cat/lr/03.htm

This is what they write about how to use this gauge:
'General purpose pressure gauges for industrial use. Suitable for gaseous and liquid media that will not obstruct the pressure system or attack copper alloy parts.'

The shop, however, told me this gauge wouldn't be able to handle contact with steam, and I would therefore have to buy a more expensive all stainless-steel one. However, re-reading the specs for the gauge in the link above, I get the impression that it would probably be fine for use with a La Pavoni. What do you think?

Another question: you mention that you've used a 1$ nut. What kind of nut is this, and why was it necesssary to use it?

Oh, and the most important question of all - what has the gauge taught you? Is it helpful at all?

Lots of questions. Hope you can help me out!

cheers ritske

[bobby yarrow]

Well, as to parts, I just bought the La Pavoni branded gauge. Upon receipt of that, I discovered I also needed a coupling nut, available through the US La Pavoni distributor. The total cost was outrageous for what it is; a plastic gauge normall costs $5 or so, and a coupling nut should run about $1, and my recollection is that buying the La Pavoni cost me roughly 10X that. I'd guess the mark-up is about 1000% over normal retail, but I think that's La Pavoni, not the distributor.

Utility is, I have to admit, pretty limited. It confirmed that my release valve really does start to release at .8, and starts to really howl 1.0. I still watch the gauge -- it's nice to know when it's approaching .5, cause I'll lift the lever and insert the portafilter -- but it's really not all that useful.

[j7on]

Here!

This is what i meant with adding a useful pressurestat to your Pavoni:



You think it could be done?

[espressme]

Hi Bobby,
snip
The shop, however, told me this gauge wouldn't be able to handle contact with steam, and I would therefore have to buy a more expensive all stainless-steel one. However, re-reading the specs for the gauge in the link above, I get the impression that it would probably be fine for use with a La Pavoni. What do you think?
cheers ritske

Hi,
IMHO some gauges are made with no path for the measured fluid to reach the internal mechanism of the gauge. They have a separate chamber of fluid in the gauge and a diaphragm or piston between it and the measured fluid.. This is to prevent the corrosion of, and possible rupture of the "Bourdon tube" which is the question mark shaped actuator in most pressure gauges. That prevents a high pressure volume of fluid being released into the glass faced dial assembly which could possibly cause a blowout. Some high pressure gauges even have a "blowout" panel placed into the back for additional operator safety.

See Wikipedia article about pressure gauges:
http://en.wikipedia.org/wiki/Bourdon_tube
Cheers
Espressme

[Ritske]

Interesting! So, if I understand you correctly, it wouldn't really matter what kind of pressure gauge you used? A cheaper model should work as well?

cheers ritske

[espressme]

Interesting! So, if I understand you correctly, it wouldn't really matter what kind of pressure gauge you used? A cheaper model should work as well?

cheers ritske

Hello Ritske,
Yes, ....for a short while! I would tend to believe that the inexpensive gauge may not have the separate fluid circuit safety/anti-corrosion feature. So, IMHO it would degrade in accuracy over time and possibly fail completely after being subjected to water vapor at high temperatures. See various photos of insides of older boilers and kettles and their accumulated boiler scale. The Bourdon tube is usually copper or similar material and subject to all the problems of a boiler partially filled with standing water due to the condensation that forms when cooling. Some low pressure gauges may be of a diaphragm type and have a different mechanism. Then the dual fluid path would be different but serve the same purpose.
'sall I can think of!
Best Regards
Espressme

[Ritske]

Hi espressme,

Ah - I just re-read your first post and I see I misunderstood you. It does make a difference what gauge you use - you need one with a 'separate fluid circuit safety/anti-corrosion feature'. Cheers - makes sense! Seems the shop wasn't just trying to get me to spend more money on a fancier gauge i didn't really need, then.

ritske

[espressme]

Hi espressme,

SNIP... Seems the shop wasn't just trying to get me to spend more money on a fancier gauge i didn't really need, then.

ritske

I didn't say that either!!
Cheers
Espressme

[Ritske]

No, of course not! That's just the impression I got after I had misunderstood your post.

cheers ritske

[Alchemist]

Since the models are not too out of line, I wanted to jump in here with the pressure gauge I added to my Gaggia Factory.

I didn't get so lucky with plug and play fittings, so I had to get inventive. It is attached to the steam wand, with the wand valve left open. I was worried for a while there about "false" pressure, and the need to relieve it, but something in the design does not promote it. I get and have to relieve it in my Olympia, but never the Factory.



And it may not be as "useful" as a grouphead pressure gauge, but it serves very well to keep my shot temperatures dialed in.

[arriflex]

If anyone is still receiving posts to this thread, could someone please let me know what the actual thread sizes are for the Pavoni? I have an older two switch Europiccola that the Pavoni $15 sight gauge adapter fits into, but I cannot figure out what the threads are on either side. The gasketed sight glass side appears to be straight threads in some sort of fine metric, but the gauge side is really close to 1/8" npt without actually being a proper fit.
TIA