La Pavoni Europiccola boiler pressure too high

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LakayM

#1: Post by LakayM » Oct 04, 2019, 11:10 pm

Hello,

I recently installed a pressure gauge on my Europiccola (Millennium), and was surprised that it indicated my machine was cycling on and off at a boiler pressure of 1.2 - 1.3 bar. I understand that the normal setting would be in the range of .8 bar, and I would appreciate your suggestions on how to proceed:

1. Could the pressure gauge be miscalibrated, even though it rests at zero when cold?

2. I checked if I could adjust the pressurestat, but the previous owner appears to have wrapped a cable tie around it which I could not move (see picture)

3. The boiler is clean, and I do not see scaling in the opening of the tube to the pressurestat: do you suggest I disconnect the pressurestat and check the tube for scaling, or would this be a difficult operation and require a special sealant to put back?

4. Could the pressurestat itself be malfunctioning and require replacement?

Thanks -

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SeekingGodShots2

#2: Post by SeekingGodShots2 » Oct 05, 2019, 12:25 am

1.2 to 1.3 is on the upper end of acceptable pressure. What's the high and low range when the pressurestat cycles?

You can snip off the cable tie with a pair of mini-diagonal wire cutter. In the same orientation, turn to the right or clock-wise a few clicks and cycle your machine - that is toward the black plastic block. Mark the setting and take a photo for reference if you must adjust it further.
LMWDP #548

LakayM

#3: Post by LakayM » Oct 05, 2019, 1:03 am

The pressurestat turns on at 1.2 and off at 1.3.

Any idea why the previous owner may have covered the adjustment ring with the cable tie? I'm afraid of breaking something if I force the ring to turn.

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drgary
Team HB

#4: Post by drgary » Oct 09, 2019, 10:59 pm

Pressure should be set at 0.8 or 0.9 bar, so you can cruise below brew temperature and use half pumps to pull shots at the desired temperature. If you haven't done so it's well worth adding a thermometer or a temperature strip to the outside of the group.

Also I see the start of rust. You'll want to take care of that now because it can get out of hand on machines like yours, where the base is made of plain steel and chrome-plated on top. The rust usually starts developing if there's a steam leak somewhere.

Maybe the prior owner set the pressure incorrectly and put the cable tie over it so no one would change it? Some of these La Pavoni pressurestats are sealed with paint so you can't change the settings.

How to adjust the LaPavoni / Gaggia pressurestat
Gary
LMWDP#308

What I WOULD do for a good cup of coffee!

LakayM

#5: Post by LakayM » replying to drgary » Oct 28, 2019, 10:55 pm

I'm a bit puzzled regarding the temperature behavior of my LP. I thought that my higher than normal boiler pressure of 1.2 - 1.3 bar would cause the water coming out of the group head to be at a higher temperature than the suggested 195 - 205ºF range.

My machine reaches its cruising temperature in about 5 minutes. After giving it another 5 minutes for the group head to heat up, I lifted the lever and measured the water temperature directly coming out of the group head (the portafilter was not attached). The temperature was 187ºF.

Other than either my (new) pressure gauge or thermometer being miscalibrated, any ideas on why my boiler would register a high pressure level and yet result in a relatively cool water temp?

Yes, I am concerned about the rust developing in the base. However, until I've gotten up enough nerve to dismantle the wires, I've tried the semi-solution of sandpapering as much of the rusted areas I can reach, and wiping on a light coat of WD-40. I've also removed the black plastic base cover, and raised the machine on small shims to improve air circulation in the base. I'm trying out this less-than-ideal set up until I gain the confidence to work on the wiring.

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drgary
Team HB

#6: Post by drgary » Oct 29, 2019, 12:57 am

Manny, as you quoted: "use half pumps to pull shots at the desired temperature." The half pumps fill the upper part of the group with water and heat it up. (A full pump would release water through the shower screen.) If you don't use these half pumps, the group can be at a lower starting temperature. And that's the point. This gives you a range of temperatures, which you can adjust for the coffee you're using.

If you decide to do rust-proofing, this thread may help. On the second page you'll see how I used rust-resistant coating.

Servicing Boiler Gaskets and Base on La Pavoni Millennium Model
Gary
LMWDP#308

What I WOULD do for a good cup of coffee!

vit

#7: Post by vit » Oct 29, 2019, 8:51 am

LakayM wrote:I'm a bit puzzled regarding the temperature behavior of my LP. I thought that my higher than normal boiler pressure of 1.2 - 1.3 bar would cause the water coming out of the group head to be at a higher temperature than the suggested 195 - 205ºF range.

My machine reaches its cruising temperature in about 5 minutes. After giving it another 5 minutes for the group head to heat up, I lifted the lever and measured the water temperature directly coming out of the group head (the portafilter was not attached). The temperature was 187ºF.
Did you purge air from the boiler before that? Otherwise, pressure is higher than expected for the temperature
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LakayM

#8: Post by LakayM » Oct 29, 2019, 10:52 pm

I tried adding 5 half pumps to my routine this morning, and the water temp rose from the previous 187º to about 190ºF. I'll be doing more experimenting on this and see what gets me to the 195-205º range.

Thanks for the link, Gary. As I said, I still have to gather up enough nerve to dismantle the wiring, and the process you went through looks a bit daunting - but at least now I have a better idea of what's involved. Wish me luck!
drgary wrote:Manny, as you quoted: "use half pumps to pull shots at the desired temperature." The half pumps fill the upper part of the group with water and heat it up. (A full pump would release water through the shower screen.) If you don't use these half pumps, the group can be at a lower starting temperature. And that's the point. This gives you a range of temperatures, which you can adjust for the coffee you're using.

If you decide to do rust-proofing, this thread may help. On the second page you'll see how I used rust-resistant coating.

Servicing Boiler Gaskets and Base on La Pavoni Millennium Model

LakayM

#9: Post by LakayM » Oct 29, 2019, 11:02 pm

Yes I do purge the air before pulling my shot (although I seem to have read somewhere that this step wasn't as critical with Millenniums). In fact, I usually steam my milk before pulling a shot, and then wait for the pressure to stabilize.
vit wrote:Did you purge air from the boiler before that? Otherwise, pressure is higher than expected for the temperature