1978 La Pavoni Europiccola Wiring Help Request

A haven dedicated to manual espresso machine aficionados.
ben0

#1: Post by ben0 »

Hi everyone,

I've had a 90% restored 1978 Europiccola sitting on my work bench for months now. I originally went through the process of completely stripping and cleaning up the machine, only for it to be completely non responsive when I plugged it in for the first time. At that point, I decided I would update all the wiring and update the heating element, as well as add a pressurestat for safety. However, between that time and now, my wife and I (mostly my wife) had a baby and work has been busy and the world has been experiencing a pandemic . . . and I have an unwired la pavoni still sitting and not producing coffee.

As much as I can blame those different life events for my inability to finish this project, the main issue is that I straight up do not understand how the heck I'm supposed to wire this thing. Part of the issue is the mixing of the different electronic components (old-style three-way switch with a new two-pronged stainless HE plus pstat, for example) and the other part is that I've never done anything like this in my life. I have looked at countless diagrams and either haven't been able to figure out what I'm looking at or realized that the diagram was for components completely different from what I am working with. I am sure the basic theory is largely the same across machines, but my complete novice style and an inherent fear of electrocuting myself / burning down my house have given me a serious case of paralysis on this project. When I took apart and rebuilt the machine originally, I documented the wiring setup, but now that so many changes have been made, it's pretty irrelevant.

So, I'm asking for your help! Can you help me make heads or tails of this project? I've added some pictures below to hopefully illustrate what I'm working with here.

Image
Here's the bottom of the EP with the heating element installed and pstat installed. I also have the brass insert to retrofit the new SS HE in place of the original screw-on one. One thing I'm concerned about is where the ground wire should go? There doesn't seem to be an obvious place to connect that. To the right of the HE is the hole/grommet where the power cord comes through (110V).

Image
Here's the outside view of the switch and light. The original switch caved in so I found a replacement online. The light is original, but I haven't been able to confirm if it is functional, as when I connected the machine to power originally, nothing responded. I'm hoping it works.

Image
Took a quick picture of the replacement power cord I purchased for the machine. The ground element is a new thing for me to deal with as the original power cord didn't have a ground on it. Quick question (to really illustrate my ignorance on electrical exercises) - which of the three wires coming out of the end is the ground? White, grey, black? I feel like I should know all this . . .

Image
The new element with pressurestat.

Image
Close shot of the pressurestat.

Please let me know if there are any other pictures I can provide that would be helpful to figure this out, and sorry for the long post and my obvious ignorance on this stuff! I appreciate any help you all can provide!

RobAnybody

#2: Post by RobAnybody »

Hi,
First things first; black is phase wite is neutral and green is ground. As far as i can see the main issue will be the switch, originally you would just run the current trough either the high or the low wattage element. The new style element looses the high/low option (which is no longer needed due to the pressostat.)
Essentially your wiring has become like this 1992 Europiccola:
http://www.francescoceccarelli.eu/La_Pa ... 06_ERH.htm here brown is phase blue is neutral and yellow/green is ground in the power cord. On the machine every color has it's own function.
You can wire the switch such that both the high and low setting do the same thing. So Taking the '92 Europiccola as a guide;
Ground connects to a screw on the side of the heating element. The phase connects to the pressostat on the pin next to the adjustment screw. The other pin connects to both one oin of the indicator light one of the prongs the heating element.
The neutral connects to the central pin of your switch and one (or both) of the other pins connect via the thermofuse to the other prong of the heating element. There is a second connection from the element side of the thermofuse to the other pin of the indicator light. This should make sure the light indicate when the element is on and doesn't work when the thermofuse failed.

One other thing to mention, you have to replace the spring inside your overpressure valve. You currently have the old spring wich will start to vent at +/- 1 bar, the new spring will vent at 1.4/1.5 bars. Make sure you hold the base of the overpressure valve with an extra spanner (metric size 16) when you unscrew the top of the valve to take out and re-install the spring.
Cheers!
Rob
LMWDP #647

User avatar
homeburrero
Team HB

#3: Post by homeburrero »

Rob is correct about the switch and the pressure release valve being designed for a dual-element, no pstat machine. For info on how those are wired up you can refer to this thread: 1974 La Pavoni Europiccola 3 position switch wiring?. One thing you'll find there that applies to you has to do with knowing which pin on the back of the switch goes with the 'I' depressed and which goes with "II".


If you want to rig something that uses your current element and switch I think you have some options to consider:

First, wiring the indicator light in parallel with the element terminals will make it light when the element is powered. Similar to the green light on modern machines. But those machines also have a red light that tells you the on/off switch status. You may prefer that your red light be lit whenever the switch is on, so that you have a clear reminder to help keep you from accidentally leaving the power switch on when you finish.

Second, replacing the spring and mushroom on the pressure release valve, to make it a proper safety valve, and wiring the switch to be simply on or off will allow the machine to function like a modern one -- no hissing from the release valve and a single pressure setting that can be adjusted as you wish.

But there is another option if you want to get creative and have a unique functionality. You can keep the original pressure release valve spring, perhaps shim it with a thin washer or two very cautiously (do NOT modify it by stretching the spring) to release slightly higher, maybe around 1.1 bar. Then wire the switch so that the switch's 'I' setting terminal connects to the pStat and the 'II' setting bypasses the pStat. Then adjust your pStat to give you a reasonable idle/brew pressure, maybe 0.6 or 0.7 bar - something below the point where the relief valve hisses.

Then your operation mode would be to warm up and brew in the I position. It will warm fast, at 1000 watts on that setting until it hits the pStat setpoint. If you want more heat, perhaps while bringing the group temp up, you can switch to II for a while to force the element on. You would pull shots while on the I setting, then when steaming you can put it on II and let it come up to full hissing pressure before opening the steam wand. If you leave it on II, the element stays powered on and hisses away steam (Just like the original dual switch version.)

If you aren't good at electrical wiring you may want to enlist some help. Someone with a good multimeter and crimping tool (and know-how to use them) would be good. You'll also need a pressure gauge to help you set that pStat. You can fashion something that works using a hardware store gauge and a length of 1/4" brakeline hose, and a couple hose clamps. It slips onto the steam wand.
Pat
nínádiishʼnahgo gohwééh náshdlį́į́h

ben0

#4: Post by ben0 »

Thank you both for those replies, Rob and Pat!

@Rob:
Question about lacking the high/low setting - Shouldn't the water be heated to different temperatures for pulling shots/producing steam? I'm not sure I understand why the pressurestat would allow for hot enough steam temperatures without burning the espresso (without the additional control feature of a second temp setting for the HE).

And as far as the ground, would you recommend just connecting it to one of the bolts on the side of the HE (where the HE is bolted to the base)?

Also, thanks for the heads-up about the overpressure valve! I'll definitely take care of that. On that topic - do I just need to replace the old spring (with this one: https://www.theespressoshop.co.uk/en/La ... -2249.aspx) or do I also need to replace the existing safety valve with the new anti-vac version (https://www.theespressoshop.co.uk/en/La ... -2253.aspx)? My assumption is that both need to be replaced...

@Pat:
Thanks for that list of options. As for the light, I think it would make sense to simply wire it to be ignited when the element is powered. Definitely don't want to blow my element by running it dry. Your third option answers my prior shot vs steam question (and seems like a desirable approach), but it sounds like it way be over my head from an execution standpoint. I would love to find somebody in nearby (Washington, D.C. area) who could help me complete this project, but not sure where to look for that. Given that I don't know anybody with this type of skillset, I'll have to see if I can find a local business who either do small appliance repair work or maybe an espresso tech (although this may be too small a project to bother them with).

Thanks also for the info on setting the pStat.

Cheers!

User avatar
Balthazar_B

#5: Post by Balthazar_B »

ben0 wrote:Thank you both for those replies, Rob and Pat!

@Rob:
Question about lacking the high/low setting - Shouldn't the water be heated to different temperatures for pulling shots/producing steam? I'm not sure I understand why the pressurestat would allow for hot enough steam temperatures without burning the espresso (without the additional control feature of a second temp setting for the HE).
Yes, a clever solution for two different temperatures. The first setting will let you use the pstat to set the approximate temp for your coffee. The second setting, in concert with the more tightly wound spring, will let the water heat up more until the piddly but superheated boiler merrily lets off steam (literally). This will provide higher pressure for milk steaming. Now if you don't make many milk drinks, this might overcomplicate things for you.

And can certainly understand your reluctance before beginning this project. When it comes to electricity, always keep Johnny's astute observation in mind...
- John

LMWDP # 577

User avatar
homeburrero
Team HB

#6: Post by homeburrero »

ben0 wrote:Also, thanks for the heads-up about the overpressure valve! I'll definitely take care of that. On that topic - do I just need to replace the old spring (with this one: https://www.theespressoshop.co.uk/en/La ... -2249.aspx) or do I also need to replace the existing safety valve with the new anti-vac version (https://www.theespressoshop.co.uk/en/La ... -2253.aspx)? My assumption is that both need to be replaced...
I think your best bet is to just get the correct strong safety spring (~ 6 coils) for the old fitting. To upgrade to the newer anti-vac version you'd need to replace the entire body, which can be a pain. Stefano sells the one you want complete with a plastic mushroom that works better than the old steel ball and swaps right in place of your old ball and spring: https://www.espressocare.com/products/i ... fessionale
Balthazar_B wrote:Yes, a clever solution for two different temperatures. The first setting will let you use the pstat to set the approximate temp for your coffee.The second setting, in concert with the more tightly wound spring . . .
I should probably say that my idea of this change would not use the stronger safety valve spring. I think that would permit too high pressure/temperature that might even trip the safety thermoswitch. If I were to do this I'd stick with the existing weaker spring (~12 coil) perhaps strengthened slightly with shims behind the spring. Depending on the steam tip, a 1000 watt heater with the steam wand full open will drop down to the 1 bar neighborhood anyway, even with the element steadily on.
Pat
nínádiishʼnahgo gohwééh náshdlį́į́h

RobAnybody

#7: Post by RobAnybody »

ben0 wrote:@Rob:
Question about lacking the high/low setting - Shouldn't the water be heated to different temperatures for pulling shots/producing steam? I'm not sure I understand why the pressurestat would allow for hot enough steam temperatures without burning the espresso (without the additional control feature of a second temp setting for the HE).
The old euripicolla with the double heating element uses a different system than the new version with pressostat and single heating element.
On the old setup the overpressure valve prevented the water from becoming to hot for brewing on the 1 setting by constantly venting the overpressure. In the new setup the setting of the pressostat takes care of that by switching off the heating element when the desired pressure is reached.
Indeed you then have to compromise between optimal browning temperature (pressure between 0.7-0.8 bar for most medium-dark roasts) and steaming power (0.9-1.1 bar).
Using a single hole steam wand tip will help getting additional steaming power with a lower pressostat setting.

Homenurrero's suggestion for bypassing the pressostat on the 2 setting would allow you to keep the functionality of the old setup.

Changing the overpressure valve for the new antivac valve is not really necessary in my opinion. You'll get rid of the lever lifting after a shot when the machine cools down but from what I've read most users still have to vent the headspace on warming up even with the anti-vac valve installed.
LMWDP #647

ben0

#8: Post by ben0 »

Thanks again for all of these helpful responses!

Whether I go with the updated version (new spring) or stick with Pat's suggestion for the modified functionality, is it still recommended to replace the steel ball with the plastic mushroom?

Still working on figuring out the wiring exactly, but this other information is helping to identify the functionality I want to maintain with the machine.

User avatar
homeburrero
Team HB

#9: Post by homeburrero »

ben0 wrote:is it still recommended to replace the steel ball with the plastic mushroom?
It's often recommended, because the steel ball sometimes gets pitted or corroded and starts to hiss. The teflon seals much better and will never corrode. But not necessary if the steel ball is nice and shiny. A 30 yr old LP Pro that I had, now a friend's daily driver, is still working fine with a steel ball.
Pat
nínádiishʼnahgo gohwééh náshdlį́į́h

ben0

#10: Post by ben0 »

Ok, it's been awhile since I have been on this thread, as I've been trying to understand what the heck I'm doing here. To this point, I haven't actually done any wiring. However, I have been working on figuring out the logic behind the continuity and the wiring of the machine. As a result, I have put together several diagrams that illustrate four things (I hope):

First off, the image below shows the continuity on a I-0-II switch, like the one on my '77 La Pavoni (I made a mistake in the original title of this thread; my machine is a '77, not a '78). This guidance regarding the switch should work for any of the machines from 1973-1977 with the three-position switch, per Francesco's guide (http://www.francescoceccarelli.eu/lapavoni_ep_eng.htm).
Image
As I tried to demonstrate in this diagram, when the switch is in the 0 "neutral" position, there is no continuity between any of the prongs.
When the switch is on the I "minimo" position, prongs b and c have continuity.
When the switch is on the II "massimo" position, prongs a and b have continuity.

When I first purchased the machine, it was wired like this:
Image
Here is my diagram:
Image
Because the machine has never worked while I've owned it, I'm not sure how there could be any distinction between the I and II in terms of wattage. Strangely, the heating element on my original machine was a two prong screw in element, rather than the four-prong element I see on pretty much every other machine online. As you can see from the diagram, both the I and the II settings are going to do the same things, simply because the voltage delivered is the same. Am I missing something? You can also see that both the I and the II setting should illuminate the light, meaning the light will only be lit when the boiler is actually receiving power.

In my correspondence with Stefano, he was kind enough to send me the following diagram for the new setup I have (see my earlier posts for more info), albeit with the Green on/off switch:
Image

Using this information along with my understanding of the way my switch functions, I put together the following diagram illustrating how I think it ought to be connected for my machine:
Image
Now, my idea is that, as suggested by Pat above, I set the machine up for modified functionality. So, I would wire the Pstat in line with the "I" setting on my switch. This would, if I understand it correctly, make it so the Pstat is only powered when the switch is in the "I" position, therefore allowing me to reach a higher temperature/pressure by bypassing the Pstat in the "II" position (illustrated further below). Does this diagram make sense, or am I completely off on how it should work?

So, for the "II" setting, I put together the following diagram:
Image
In this diagram, selecting "II" on the switch gives me the continuity needed to power the HE directly and takes the Pstat out of the loop. It closely represents the original setup on the machine, but without the (seemingly arbitrary) second application of wiring to the "I" setting.

To combine these two wiring setups for modified functionality, I put together the following diagram:
Image
I tried to demonstrate the wiring directly responsible for the "I" setting as grey and light blue, whereas the "II" setting wiring is black and dark blue. Does this look properly put together? I'm fairly certain that the switch's regulation of I and II will make this work, but as I've said (and demonstrated) throughout this thread, my level of expertise with electricity is firmly in the novice category.

Are there glaring errors here? Anything you would recommend changing? Thanks again for taking the time to look at this and respond if you can. Also, if my diagrams are accurate, hopefully they can help other people figure out some of their three-position switch issues. Thanks!

-Ben