La Marzocco GS3 steam suddenly too weak - Page 2

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Yuki (original poster)
Posts: 202
Joined: 7 years ago

#11: Post by Yuki (original poster) »

chrisvarghese wrote:You can just open the right side panel and have a look at the boiler, that should be pretty simple and should not affect the side steam lever. Have a look at my post on installing a side mounted steam arm, to see photos of what the inside looks like. I feel like the steam dying out maybe due to the steam valve closing in, I'm just speculating.

Here's the link to my post
DIY La Marzocco GS3 Side Mounted Steam Lever
Many thanks for the link, Chris.

I'm hoping this won't be a big deal of course. It *did* work wonderfully for about 72 hours. :) I suppose something could have come a bit loose during transportation of course.

Yuki (original poster)
Posts: 202
Joined: 7 years ago

#12: Post by Yuki (original poster) »

Peppersass wrote:Ask Dan for help.
Dan emailed me this morning. His first hunch is that it's only a matter of adjusting the side arm. I'm pretty sure I can do that (adjust the grub screw on the side of the pusher). His thinking seems to be that after transportation, sometimes this adjustment has to be re-calibrated. I'm not surprised -- there is a lot of vibration during transport -- and I hope that's all it is of course.

I replied to him asking whether I need to do this while powered/pressurized, or exactly the opposite. I don't know, so I ask rather than guess. It's off and cool at the moment.

Thanks again, Dick.

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Peppersass
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#13: Post by Peppersass »

Yuki wrote:]Btw, I do see some steam escaping at a certain point during warm-up, but then something seems to occur and it just stops. I was assuming there was some kind of pressure valve or something that reached a certain level, and that it was all normal.
If the steam you saw was coming from the right side of the drain box, it's completely normal. The vacuum breaker drain line is connected there, in the chassis rail just above the back of the drain box.

The vacuum breaker itself is attached to the upper right side of the steam boiler. Its purpose is to allow air to escape as it's pushed up by steam formed as the water boils. This prevents a loud pop when you first operate the steam valve. As the air is pushed out, you'll see steam and a bit of water coming out of the drain line connected to the drain box. Once the air escapes, the valve closes shut due to the steam pressure below and the steam/water should stop flowing into the drain box.

Note that depending on your water composition, the vacuum breaker valve may need service every 6-12 months or so. Sometimes a light layer of mineral deposits forms inside, keeping the valve from shutting completely. It's harmless, but you'll hear some hissing and see water dripping into the drain box occasionally. Even if you don't get deposits, eventually the O-ring wears out and has to be replaced. LM sells an inexpensive rebuild kit and also sells the internal components separately. Often just the O-ring needs to be replaced.

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Peppersass
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#14: Post by Peppersass »

Yuki wrote:Dick, your comments about steam inside (esp possible brain box damage) have me reluctant to turn on the steam boiler (even the machine itself, actually), but it seems necessary to do that to diagnose the problem.

Am I worrying too much?
Take the sides and top cover off, then start the machine. If you see any steam or water leakage inside the machine, turn it off immediately. If not, try the steam valve. If you see any steam or water leakage, turn off the steam valve. If the leak doesn't stop, turn off the machine.

Doubtful that enough steam or water will escape is such a short time to pose any threat to the brain box.

Yuki (original poster)
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#15: Post by Yuki (original poster) replying to Peppersass »

Didn't see those inner nuts at first. Got it now.

Thanks as always.

Yuki (original poster)
Posts: 202
Joined: 7 years ago

#16: Post by Yuki (original poster) »

Okay, top and right side are off. Machine is powering up. Nothing amiss yet.

I do notice that when manipulating the side steam lever (still attached for now) I can see down into the machine, and I can see what seems to be the "plunger". Based on its name, it would seem to me that rotation of the side arm is designed to make that "plunger" plunge in and out.

If my assumption is correct, then we may know the problem, because rotating the steam lever produces either zero or almost undetectable movement of that plunger.

Am I barking up the right tree here?

I see no signs of any prior leakage inside the machine (around any boiler fittings, etc), so that's good.

Yuki (original poster)
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#17: Post by Yuki (original poster) »

Steam I noticed before is coming from the appropriate places, as Dick mentioned. Begins at warm-up temp of about 140 F, steams pretty good into the tray for a few minutes, then cuts off completely at around 150 F.

Pressure beginning to build now in the steam boiler. No signs of any leakage at all thank goodness.

Yuki (original poster)
Posts: 202
Joined: 7 years ago

#18: Post by Yuki (original poster) »

Okay ... up to operating temps, and there seems to be nothing amiss in terms of water leakage inside. No sounds, no steam, no discoloration where water previously might have leaked.

Clearly I think, I was wrong about the "plunger". I'm getting steam, and that piece I referred to earlier isn't moving at all. So movement apparently takes place "inside" where I cannot see it.

Now, and this surprises me, I'm getting more steam, and for longer. Last night I did take the hex nut off of that steam lever, but I wasn't sure about how to proceed with the inside parts (I was only intending to remove the left side, actually), so I put it back on.

I wonder if the way I put it back on changed something. One would think not, as it's pretty straightforward (you have to apply pressure and then tighten that hex nut.

The manometer drops while the steam is operating, and of course there is a slight (but still detectable) drop off in the pressure the longer it runs. But it's running longer and stronger than it has for the past 2 days. Enough, maybe. And the recovery is as fast as I'd expect.

Over to you knowledgeable types, I think.

At this point, pretty sure we can rule out major/catastrophic damage, and if there is still a problem (or if the problem returns) it seems it's going to be in that steam arm/plunger/adjustment area.

I think I'll make some espresso, and see how it progresses. Rather mysterious. :)

chrisvarghese
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#19: Post by chrisvarghese »

From the sounds of it I think the steam lever just needs to be calibrated, just like Dan advised. How the side steam works is, there is a ramp in the lever and as you pull it, the ramp pushes the rod in the steam valve.

Try checking the steam consistency at different points of the lever. So pull it maybe 50%, steam for 1-2mins and see if its dropping (expect natural drop due to steam pressure going down). Then try similar exercise at 75%, 85%, 90%.

Yuki (original poster)
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#20: Post by Yuki (original poster) »

chrisvarghese wrote:...Then try similar exercise at 75%, 85%, 90%.
Thanks Chris.