La Marzocco GS3 suddenly silent?

Equipment doesn't work? Troubleshooting? If you're handy, members can help.
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ChristianB.
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Joined: 6 years ago

#1: Post by ChristianB. »

Hello

My Marzocco GS3 is suddenly silent when brewing? Normally the pump makes some noises, but nothing now! Why?
Best regards

Christian

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Peppersass
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Joined: 15 years ago

#2: Post by Peppersass »

Hard to tell from the video, but it looks like the pressure isn't rising to 9 BAR. Looks like it's about 3 BAR, which would be line pressure. The humming noise must be coming from the motor, but it doesn't sound like it's turning. Possibilities I can think of:

1. Pump is jammed
2. Motor is broken
3. Bad motor start capacitor
3. Bad connection at the logic board
4. Bad connection at the motor or at splice nearby

First thing to do is consult your dealer. If you don't have experience with mechanical and electrical repairs, you'll have to bring the machine to the dealer for repairs. If you're experienced and comfortable with repairs, here's what you can do:

Start by removing the pump, which isn't hard. Of course you must turn off the water first, and it's best to shutdown and unplug the machine. If the motor shaft spins properly without the pump connected, then you know the pump is jammed. It may be possible to disassemble and repair if you're comfortable with that.

If the motor shaft doesn't turn, I would check the motor start capacitor inside the brain box. If you're not familiar with how to test a capacitor, consult your dealer. The dealer might have a spare on hand you can substitute to see if your capacitor is not working.

If it's not the capacitor, then check the motor leads inside the brain box. It's possible one of the leads is loose in the large terminal block. You might be able to fix it by tightening the screw. If that's not the problem it gets more difficult. Not easy to test the voltage at the motor, and the nearby splice is covered with an insulator.

If you decide to open the brain box: Remove the back cover and gently slide the box out of the machine. Be careful not to pull on the cables too much. Remove the screws that hold the top cover on. Before putting the cover back on, make sure all the cables are securely plugged into the logic board, and be careful not to stress the cables when sliding the brain box back in the machine. Mainly this applies to the button and display cables, which can come out of their connectors when the cables are pulled.

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ChristianB. (original poster)
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#3: Post by ChristianB. (original poster) »

Thank you for your detailed answer!
Best regards

Christian

wholemilklatte
Posts: 196
Joined: 7 years ago

#4: Post by wholemilklatte »

Are you plumbed in or using the tank? Not that it would make a ton of difference in troubleshooting but making sure there isn't any debris clogging your inlet tube and/or water line would be good. If the pump is actually stuck it could be due to debris.

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ChristianB. (original poster)
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#5: Post by ChristianB. (original poster) »

No it is plumed in. This is how it sounded before http://www.youtube.com/watch?v=0P1uYXpTKSU

Do you know how I get a email notification whenever there is a new reply to this topic?
Best regards

Christian

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Peppersass
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#6: Post by Peppersass »

Notice that the pressure ramps up to 9 BAR, which is normal. That isn't happening in the first video, indicating that the pump isn't working.

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ChristianB. (original poster)
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#7: Post by ChristianB. (original poster) »

So I may need to change the pump? Is it a difficult task? and is a new pump expensive?
Best regards

Christian

wholemilklatte
Posts: 196
Joined: 7 years ago

#8: Post by wholemilklatte »

It could be any number of things. Peppersass listed a bunch of reasonable possiblities in the first post - you'll have to do some troubleshooting to narrow down where the problem is first.

The parts are all readily available, i think simply swapping the pump is relatively straight-forward. If you need to swap the motor it's a much more involved bit of work. All of the parts are readily available, in fact you can get a stainless steel version of the pump now if you want.

Start with troubleshooting first though, it may be a fixable problem that doesn't require any parts replacement.

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ChristianB. (original poster)
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#9: Post by ChristianB. (original poster) »

Attached pictures of the pump! Difficult to say what has happened? I think a new pump and hose is necessary!



Best regards

Christian

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Peppersass
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#10: Post by Peppersass »

I've never seen anything like this. Clearly there has been a leak, maybe more than one. Can't tell if it came from the pump or one of the hoses.

Of even more concern is the extreme amount of mineral residue coating the pump and hose fittings. You must have very hard water, which is very bad for espresso machines. Have you tested your water for hardness? Are you using a water softening system?

I suspect the mineral deposits are related to the pump failure. It could be that the vanes inside the pump are so caked with minerals that they can't move anymore.

The pump and hoses need to be replaced, but it's a good bet that there are heavy mineral deposits in other parts of the machine that will eventually cause serious problems. In that case it will need to be descaled, and that will be a very tricky job if the amount of scale elsewhere in the machine is as bad as the scale on the pump. Other parts may need to be replaced.

I think you should have the machine serviced by a qualified La Marzocco technician.

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