La Marzocco Auto-Fill Fix
Hello all. At the shop in which I work, our LM Linea is not auto-filling. It is still operational if we manually fill the tank, so we know it is not the pump. I have a hunch that we have a problem with the Auto-Fill valve, possibly a build-up of scale or some like blockage. Any other ideas?
Replies to This Discussion
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Permalink Reply by Brady on
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The fill solenoid would be my first check. Is the coil active and working (cause that's easiest to check) then remove and check the valve. Or hit it with a hammer.
Got a good tech?
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Permalink Reply by Phil Proteau on
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I would look at the level probe too, sometimes you can just wipe them off and start up again. The rule of thumb is to rule out the easy fix first before you go taking apart a valve or something.
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Permalink Reply by Fraser Jamieson on
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My first guess would be the probe.
If you pull the wire off it, it should start to fill the boiler. If it picks the coil but doesn't open the valve then the valve could be dirty.
On our machine we had both a probe problem, at one point, but also a board problem at another time. The board cost a few bucks so I hope that's not what your problem is.
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Permalink Reply by Andrew Tagge on
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We took the wire off the probe, but nothing happened. Neither the pump nor the valve activated. Would this mean that there is a problem with the probe? We have taken the probe out and cleaned it off (it was rather dirty), but that also fixed nothing. Also, could it be a problem with the wire leading off the probe to the electrical box?
Fraser Jamieson said:My first guess would be the probe.
If you pull the wire off it, it should start to fill the boiler. If it picks the coil but doesn't open the valve then the valve could be dirty.
On our machine we had both a probe problem, at one point, but also a board problem at another time. The board cost a few bucks so I hope that's not what your problem is.
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Andrew Tagge said:We took the wire off the probe, but nothing happened. Neither the pump nor the valve activated. Would this mean that there is a problem with the probe? We have taken the probe out and cleaned it off (it was rather dirty), but that also fixed nothing. Also, could it be a problem with the wire leading off the probe to the electrical box?
Fraser Jamieson said:My first guess would be the probe.
If you pull the wire off it, it should start to fill the boiler. If it picks the coil but doesn't open the valve then the valve could be dirty.
On our machine we had both a probe problem, at one point, but also a board problem at another time. The board cost a few bucks so I hope that's not what your problem is.
That would mean that your problem is not the probe. A problem with the probe wire would more likely be a broken or cut wire, which would create an overfill situation, so that leads me to think that the probe lead is ok.
With the boiler reasonably full, locate your fill solenoid coil - the little black box on the valve. Find a parts schematic if you need help locating it. Remove the large flat nut that holds it onto the valve (being careful not to touch any live wires) and slide it partially up the valve stem - move it by 1/4" or so. Then remove the probe wire and see if the solenoid pops back down into place. If it does, then your coil and fill circuit are working. If there is a force tugging it back down as you are trying to pull it up, they are both good as well.
If your coil is working I'd suspect your valve. Probably needs to be disassembled and cleaned (or tapped with a ball peen hammer). If there is no tug or movement, your solenoid coil or circuit are the problem and you need to perform additional troubleshooting.
Please consider calling a tech.
Good luck.
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Permalink Reply by Mike Sabol on
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Electrically, the only thing that would explain those symptoms would be the wire that leads to the fill probe is shorted to the frame somewhere. When you take the wire off the fill probe and the unit doesn't engage the pump or the fill valve then the CPU thinks there is water in the unit and the circuit is complete.
Andrew said that the manual fill is working fine which means there is no problem with the fill valve or pump. The manual fill on a Linea is a button that engages the fill valve and pump, circumventing the CPU logic, but utillizing the same electrical/hydraulic fill circuit. I was thinking that the probe was shorted to the tank via scale build up until he said that he took the lead off the probe and nothing happened.
I would look for any loose connections at the CPU. Also look to verify that the fan is working and blowing the air OUT of the chassis. When the fan fails and stops, the CPU can start to get wacky. That one is a long shot though.
You might need a tech for this one.
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So, before deciding to take apart the valve and possibly create a larger issue, I noticed that, like Mike said, when I press the manual fill, the wire on the valve jumps. Therefore, water is still traveling through the valve and it must not be clogged. We already know the probe is clean. That leads me to believe the problem indeed is electrical. What all should be checked/replaced/etc. Any other thoughts or ideas?
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Mike Sabol said:
Andrew said that the manual fill is working fine which means there is no problem with the fill valve or pump. The manual fill on a Linea is a button that engages the fill valve and pump, circumventing the CPU logic, but utillizing the same electrical/hydraulic fill circuit. I was thinking that the probe was shorted to the tank via scale build up until he said that he took the lead off the probe and nothing happened.
Ahhh... ok. Haven't had to "manual" fill a Linea before - I have a couple that I've worked on, but nothing requiring a manual fill operation. Sorta assumed that it was a mechanical valve like on other manufacturers' machines... guess I shouldn't assume, eh? Glad this came up... I'd have looked for a manual valve for a while.
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Andrew Tagge said:So, before deciding to take apart the valve and possibly create a larger issue, I noticed that, like Mike said, when I press the manual fill, the wire on the valve jumps. Therefore, water is still traveling through the valve and it must not be clogged. We already know the probe is clean. That leads me to believe the problem indeed is electrical. What all should be checked/replaced/etc. Any other thoughts or ideas?
Trace the probe wire and look for visible pinches or shorts. Look for corrosion, moisture, or debris near the terminal. If you find none, you're done with the troubleshooting you can perform. At that point, you should call a tech.
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Permalink Reply by Kevin Ayers on
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Had a similar problem once, where nothing seemed to make sense because fill probe, fill solonoid and all components seemed to be functioning properly, but the boiler would not auto-fill. Long story short, it ended up being a bad flow-meter, that was somehow causing the "brain" to not auto-fill the steam boiler. I really didn't believe it, but, replacing the bad flow-meter fixed the problem for good. Maybe check those for proper functionality? Just my two cents...
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Just to double check, when the machine is on and you remove the wire from the fill probe nothing happens?
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Right, we took the wire off the probe and also removed the entire probe from the tank with the wire still on it and nothing engaged. Also, there are no visible shorts or pinches. I'm starting to think that there might be a problem with the CPU not registering and telling the auto-fill to activate the fill valve.
Mike Sabol said:Just to double check, when the machine is on and you remove the wire from the fill probe nothing happens?
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