Hello!

pierrox

New user here, came across this forum trying to figure out an issue with my Lelit Elizabeth and it seems there is a lot of technical knowledge here.

I have a Lelit Elizabeth and I decided to try pre-infusion. I adjusted it to 3 seconds in the hidden service menu, and 10s in the quick access LCC menu and when I run a shot the pressure gauge hardly moves at all. Something wrong with it? The pump kicks in for 3 sec as it should, but then nothing happens on the gauge (it barely gets to .5 bar) for the next 7 seconds. Machine is second hand, so no warranty.

I know the gauge works as it shows pressure when I do a regular shot. I know the steam boiler works too since I can steam milk. I tried pushing the boiler temp at 140°C and it made no difference.

Also, the EVS setting is set to 1, and the boiler is on in the LCC menu.

So I opened it. I watched several videos from Lelit insider and understood that the solenoid valve close to the group head has two functions:

- it opens when the steam boiler needs fresh water.

- it opens during steam pre-infusion.

So essentially, water can travel both ways through the hoses. The solenoid must work as the machine refills the boiler when needed. I ran tests with the top off and I can see water travelling to the boiler. During preinfusion, I couldn’t quite see water travelling the other way round, but it’s more about pressure being applied to the water than water actually travelling.

I measured the voltage at the solenoid during pre-infusion and it’s behaving as in the videos mentioned above. I have 230volts at the solenoid during the whole pre-infusion phase. So I can rule out an electrical/electronic bug.

So who are the potential culprits?

- a faulty/clogged solenoid valve? which doesn’t open enough? Water could refill because the pump pressure can sustain 10+ bars, but the 2-2.5 bars from the steam boiler can’t pass the blockage?

- faulty steam boiler? It works flawlessly at the steam wand, but it’s not using the same port to provide pre-infusion. My knowledge of coffee boilers is too lean to know if there are one way valves inside them or something that could cause the issue.

Happy to hear your thoughts. Who could be another culprit? The 3-way solenoid valve? It works during coffee extraction though.

MediumRoastSteam

pierrox - welcome. What happens when you draw 300ml of water from the hot water tap, when both boilers are on and the machine fully warmed up. Do you hear the steam boiler filling up afterwards?

If so, then that solenoid is working.

DavecUK

Welcome to the forum, sounds like it’s all set OK for steam preinfusion

https://sway.office.com/S5J4d9Jp4Y9LdVFx?ref=Link

Check out my sway, and see if all your settings are definitely correct. It could be that solenoid is simply not working, at least to the brew boiler path?

pierrox

MediumRoastSteam

Thanks guys!

I did come across your sway but I’ll double check. When I see demos and videos, the pressure gauge goes up to 2-3 bars during pre infusion. On mine it barely moves with coffee, and with the blind filter it hits less than .5 bar

Yes the boiler fills up, I even tested this without the cover and I can see the water going to the boiler (thanks to small bubbles).

During pre infusion I don’t see any movement. I’m not expecting much movement though, since the steam is just supposed to push the water sitting on the puck.

It’s very puzzling

MediumRoastSteam

Ok… so:
EVS is set to 1;
Pump run is set to 3 seconds;
Steam Boiler temp is 140C;
Steam Boiler fills, so there are no blockages and solenoid is obviously open;
Pre-infusion is set to 10s.

Try this:
Purge a little water from the hot water tap (10ml)
Purge water from the group (10ml)
Purge the steam wand

Go about making your coffee. If you use a blind basket, make sure it’s full of water. Any better? The only thing I can think of is you are doing something which is causing a void in the brew boiler, so the pressure cannot build up. Failing that, the other possibility could be that, for whichever reason, the solenoid is kept shut during steam pre-infusion.

pierrox

MediumRoastSteam Try this:
Purge a little water from the hot water tap (10ml)
Purge water from the group (10ml)
Purge the steam wand

Tried, and it’s the same. I triple checked: EVS=1, 4 seconds BLS1/2, 10seconds total PI. And it’s still the same. With the blind basket on, the gauge moves about ¼ of a graduation.

I don’t quite get how a boiler could be faulty, it’s very basic in its operation. The solenoid valve? It’s supposed to be a 2 way from what I understand.

pierrox

I’ll try this in a minute. The boiler has plenty pressure since I can steam milk pretty quickly (so much faster than my previous Victoria!)

I will clean the solenoid. It gets power during pre infusion, I measured it with a voltmeter - got the idea from a video by Lelit Insider.

On yours, if you start a shot without the porta filter, does water run during all the pre infusion phase? And if so, at what rate?

MediumRoastSteam

pierrox - water does run during the pre-infusion phase. I can’t quantity the rate. It’s more like fast flowing drips rather than a steady stream if that makes sense.

pierrox

MediumRoastSteam Makes sense, from my understanding it’s pushed from the steam boiler. With no resistance from the filter, it flows. Mine does this too.

MediumRoastSteam

Indeed it’s puzzling. What about when you use bloom pre-infusion. What do you get?

pierrox

When I press the button, the pump runs for 4 seconds (as set in the factory menu), pressure builds up to 9 bars. Then the pump stops, the machine waits until 10s (adjusted in LCC) and then it resumes. Pressure drops during the pause as nothing sustains it.

Is this how it’s supposed to work?

MediumRoastSteam

pierrox Is this how it’s supposed to work?

Yep… I’m baffled.

Cuprajake

No idea what’s going on, but
Giphy - French Hello GIF by WWE

DavecUK

MediumRoastSteam Me too, I can only think the solenoid valve isn’t working properly.

pierrox

Agreed. The boiler works as it should. And it fills up no issue. I know the previous owner had it serviced before the warranty ended and said the 3-way had been changed, but he wasn’t 100% sure. I will pull out the boiler solenoid to see if I can clean it. Or maybe they put the wrong one - my hope.

MediumRoastSteam

pierrox - keep us posted. I’m quite interested.

So, based on the experience so far, it is fair to say the solenoid is not blocked because:

The steam boiler refills (path: manifold to steam boiler, I.e.: reverse)
It draws hot water from the steam boiler, as the steam boiler refills when you purge 300ml of water or so from the hot water tap (path: steam boiler to manifold, manifold into brew boiler, brew boiler onto tap)

Could it be it is as simple as that it’s not doing ANY pre-infusion at all, I.e.: the solenoid is not opening? If so, could it be a bad connection in the gicar box?

Looking at your picture, it seems that the hot water tap solenoid was serviced as it has some ptfe tape around it - at least that’s what it looks like.

DavecUK

If they wired the solenoid wrong or used the wrong one, that would account for it. As it might be never switching to the way from service boiler to brew boiler,

pierrox

Hard to tell but on the photo in the first post, you can see(ish) that the red wire goes to the connector closer to the grouphead. The other wire (a white one) goes to the other connector and is coming from the hot water tap. No idea if it’s the way it should be.

I noticed that Lelit uses many different solenoid valves. Quite a few different 2-way valves. According to a diagram I saw, the correct one is 9700041

https://lamacchinadelcaffe.com/en/elettrovalvole-lelit.html

https://www.1st-line.com/technical-support/lelit-technical-support-page/parts-diagram-lelit-pl92t-elizabeth/

pierrox

Worked on the solenoid. Spoiler alert: no improvement.

Today I removed the steam solenoid valve and cleaned it.

If you have an Elizabeth, maybe you could tell me if it’s the same. Researching Google for a bit makes me think it’s the correct one, but who knows.

I opened it, didn’t seem especially dirty. And the spring loaded piston moves freely. One thing I didn’t try was activating it as I got a bit wary of feeding it 220v in a wet environment. Cleaned it with descaler, put it back and reinstalled. Before that, I noticed it’s not symmetrical inside. Hence the marking 1 and 2 on the outside. I put it back the way it was, which I think is correct according to a photo on Clive Coffee. Again, if you have an Elizabeth at hand, maybe you could confirm that the “1OLAB” port faces the front of the machine?

Whilst it was out, I blew into the steam boiler hose and could hear bubbling inside. And I sucked on it and could get water from it. Didn’t feel any strong resistance either way.

Then I reassembled everything and it’s still the same. 😢

I might try to put the solenoid the other way around, but later as the machine is too hot to work on.

MediumRoastSteam

The other possibility is that all is well, but your gauge is under reading?